Use milkypostman's powerline fork

This one is actively maintained as opposed to jonathanchu's version.

Here's the test-recipe.sh output:

```sh
*** Testing el-get recipe /home/fgallina/Code/Projects/el-get/recipes/powerline.rcp ***
`flet' is an obsolete macro (as of 24.3); use either `cl-flet' or `cl-letf'.
`flet' is an obsolete macro (as of 24.3); use either `cl-flet' or `cl-letf'.
el-get-init-and-install: install (cl-lib powerline)
el-get-init-and-install: init nil
el-get: updating autoloads for cl-lib
Wrote /tmp/el-get-test-home/.emacs.d/el-get/.loaddefs.el
(No changes need to be saved)
(No changes need to be saved)
el-get: byte-compiling autoload file
Wrote /tmp/el-get-test-home/.emacs.d/el-get/.loaddefs.elc
el-get: evaluating autoload file
Loading ~/.emacs.d/el-get/.loaddefs...
el-get initialized package cl-lib
cl-lib installed: This package has been installed successfully by el-get.
el-get install cl-lib
Running commands synchronously: ((:command-name "*git clone powerline*" :buffer-name "*git clone powerline*" :default-directory "~/.emacs.d/el-get/" :program "/usr/bin/git" :args ("--no-pager" "clone" "http://github.com/milkypostman/powerline.git" "powerline") :message "Package powerline installed." :error "Could not install package powerline.") nil (:command-name "*git submodule update*" :buffer-name "*git clone powerline*" :default-directory "/tmp/el-get-test-home/.emacs.d/el-get/powerline/" :program "/usr/bin/git" :args ("--no-pager" "submodule" "update" "--init" "--recursive") :message "git submodule update ok" :error "Could not update git submodules"))
el-get is waiting for "*git clone powerline*" to complete
"Cloning into 'powerline'...
Checking connectivity... done
"
el-get: Package powerline installed.
Running commands synchronously: ((:command-name "*git submodule update*" :buffer-name "*git clone powerline*" :default-directory "/tmp/el-get-test-home/.emacs.d/el-get/powerline/" :program "/usr/bin/git" :args ("--no-pager" "submodule" "update" "--init" "--recursive") :message "git submodule update ok" :error "Could not update git submodules"))
el-get is waiting for "*git submodule update*" to complete
""
el-get: git submodule update ok
el-get: pakage powerline checksum is 6d62f7c6ad64dd734518ad451a1a7c8a5115fcb3.
el-get-build powerline
Running commands synchronously: ((:command-name "byte-compile" :buffer-name "*el-get-build: powerline*" :default-directory "/tmp/el-get-test-home/.emacs.d/el-get/powerline/" :shell t :stdin (:load-path ("." "~/.emacs.d/el-get/" "/home/fgallina/Code/Projects/el-get/methods" "/home/fgallina/Code/Projects/el-get" "/usr/share/emacs/24.3/lisp" "/usr/share/emacs/24.3/lisp/vc" "/usr/share/emacs/24.3/lisp/url" "/usr/share/emacs/24.3/lisp/textmodes" "/usr/share/emacs/24.3/lisp/progmodes" "/usr/share/emacs/24.3/lisp/play" "/usr/share/emacs/24.3/lisp/org" "/usr/share/emacs/24.3/lisp/nxml" "/usr/share/emacs/24.3/lisp/net" "/usr/share/emacs/24.3/lisp/mh-e" "/usr/share/emacs/24.3/lisp/mail" "/usr/share/emacs/24.3/lisp/language" "/usr/share/emacs/24.3/lisp/international" "/usr/share/emacs/24.3/lisp/gnus" "/usr/share/emacs/24.3/lisp/eshell" "/usr/share/emacs/24.3/lisp/erc" "/usr/share/emacs/24.3/lisp/emulation" "/usr/share/emacs/24.3/lisp/emacs-lisp" "/usr/share/emacs/24.3/lisp/cedet" "/usr/share/emacs/24.3/lisp/calendar" "/usr/share/emacs/24.3/lisp/calc" "/usr/share/emacs/24.3/lisp/obsolete" "/usr/share/emacs/24.3/leim") :compile-files ("/tmp/el-get-test-home/.emacs.d/el-get/powerline") :clean-directory "/tmp/el-get-test-home/.emacs.d/el-get/powerline/") :sync sync :program "/usr/bin/emacs" :args ("-Q" "-batch" "-f" "toggle-debug-on-error" "-l" "/home/fgallina/Code/Projects/el-get/el-get-byte-compile" "-f" "el-get-byte-compile-from-stdin") :message "el-get-build powerline: byte-compile ok." :error "el-get could not byte-compile powerline"))
el-get is waiting for "byte-compile" to complete
"Debug on Error enabled globally
el-get-byte-compile: Cleaning stale compiled files in /tmp/el-get-test-home/.emacs.d/el-get/powerline/
el-get-byte-compile: /tmp/el-get-test-home/.emacs.d/el-get/powerline
Checking /tmp/el-get-test-home/.emacs.d/el-get/powerline...
Compiling /tmp/el-get-test-home/.emacs.d/el-get/powerline/powerline-separators.el...
Wrote /tmp/el-get-test-home/.emacs.d/el-get/powerline/powerline-separators.elc
Compiling /tmp/el-get-test-home/.emacs.d/el-get/powerline/powerline-themes.el...
Wrote /tmp/el-get-test-home/.emacs.d/el-get/powerline/powerline-themes.elc
Compiling /tmp/el-get-test-home/.emacs.d/el-get/powerline/powerline.el...
Wrote /tmp/el-get-test-home/.emacs.d/el-get/powerline/powerline.elc
Done (Total of 3 files compiled)
"
el-get: el-get-build powerline: byte-compile ok.
el-get: updating autoloads for powerline
Generating autoloads for powerline/powerline-separators.el...
Generating autoloads for powerline/powerline-separators.el...done
Generating autoloads for powerline/powerline-themes.el...
Generating autoloads for powerline/powerline-themes.el...done
Generating autoloads for powerline/powerline.el...
Generating autoloads for powerline/powerline.el...done
Saving file /tmp/el-get-test-home/.emacs.d/el-get/.loaddefs.el...
Wrote /tmp/el-get-test-home/.emacs.d/el-get/.loaddefs.el
(No changes need to be saved)
(No changes need to be saved)
el-get: byte-compiling autoload file

In toplevel form:
../.loaddefs.el:41:1:Error: Cannot open load file: powerline-themes
el-get: evaluating autoload file
Loading ~/.emacs.d/el-get/.loaddefs (compiled; note, source file is newer)...
require 'powerline
el-get initialized package powerline
powerline installed: This package has been installed successfully by el-get.
el-get install powerline
el-get: evaluating autoload file
Loading ~/.emacs.d/el-get/.loaddefs (compiled; note, source file is newer)...
*** Initial install successful ***
Running commands synchronously: ((:command-name "*git pull powerline*" :buffer-name "*git pull powerline*" :default-directory "/tmp/el-get-test-home/.emacs.d/el-get/powerline/" :program "/usr/bin/git" :args ("--no-pager" "pull") :message "Pulled package powerline." :error "Could not update package powerline.") nil (:command-name "*git submodule update*" :buffer-name "*git pull powerline*" :default-directory "/tmp/el-get-test-home/.emacs.d/el-get/powerline/" :program "/usr/bin/git" :args ("--no-pager" "submodule" "update" "--init" "--recursive") :message "git submodule update ok" :error "Could not update git submodules"))
el-get is waiting for "*git pull powerline*" to complete
"Already up-to-date.
"
el-get: Pulled package powerline.
Running commands synchronously: ((:command-name "*git submodule update*" :buffer-name "*git pull powerline*" :default-directory "/tmp/el-get-test-home/.emacs.d/el-get/powerline/" :program "/usr/bin/git" :args ("--no-pager" "submodule" "update" "--init" "--recursive") :message "git submodule update ok" :error "Could not update git submodules"))
el-get is waiting for "*git submodule update*" to complete
""
el-get: git submodule update ok
el-get-build powerline
Running commands synchronously: ((:command-name "byte-compile" :buffer-name "*el-get-build: powerline*" :default-directory "/tmp/el-get-test-home/.emacs.d/el-get/powerline/" :shell t :stdin (:load-path ("." "/tmp/el-get-test-home/.emacs.d/el-get/powerline" "~/.emacs.d/el-get/" "/home/fgallina/Code/Projects/el-get/methods" "/home/fgallina/Code/Projects/el-get" "/usr/share/emacs/24.3/lisp" "/usr/share/emacs/24.3/lisp/vc" "/usr/share/emacs/24.3/lisp/url" "/usr/share/emacs/24.3/lisp/textmodes" "/usr/share/emacs/24.3/lisp/progmodes" "/usr/share/emacs/24.3/lisp/play" "/usr/share/emacs/24.3/lisp/org" "/usr/share/emacs/24.3/lisp/nxml" "/usr/share/emacs/24.3/lisp/net" "/usr/share/emacs/24.3/lisp/mh-e" "/usr/share/emacs/24.3/lisp/mail" "/usr/share/emacs/24.3/lisp/language" "/usr/share/emacs/24.3/lisp/international" "/usr/share/emacs/24.3/lisp/gnus" "/usr/share/emacs/24.3/lisp/eshell" "/usr/share/emacs/24.3/lisp/erc" "/usr/share/emacs/24.3/lisp/emulation" "/usr/share/emacs/24.3/lisp/emacs-lisp" "/usr/share/emacs/24.3/lisp/cedet" "/usr/share/emacs/24.3/lisp/calendar" "/usr/share/emacs/24.3/lisp/calc" "/usr/share/emacs/24.3/lisp/obsolete" "/usr/share/emacs/24.3/leim") :compile-files ("/tmp/el-get-test-home/.emacs.d/el-get/powerline") :clean-directory "/tmp/el-get-test-home/.emacs.d/el-get/powerline/") :sync t :program "/usr/bin/emacs" :args ("-Q" "-batch" "-f" "toggle-debug-on-error" "-l" "/home/fgallina/Code/Projects/el-get/el-get-byte-compile" "-f" "el-get-byte-compile-from-stdin") :message "el-get-build powerline: byte-compile ok." :error "el-get could not byte-compile powerline"))
el-get is waiting for "byte-compile" to complete
"Debug on Error enabled globally
el-get-byte-compile: Cleaning stale compiled files in /tmp/el-get-test-home/.emacs.d/el-get/powerline/
el-get-byte-compile: /tmp/el-get-test-home/.emacs.d/el-get/powerline
Checking /tmp/el-get-test-home/.emacs.d/el-get/powerline...
Done (Total of 0 files compiled, 3 skipped)
"
el-get: el-get-build powerline: byte-compile ok.
el-get: updating autoloads for powerline
Saving file /tmp/el-get-test-home/.emacs.d/el-get/.loaddefs.el...
Wrote /tmp/el-get-test-home/.emacs.d/el-get/.loaddefs.el
(No changes need to be saved)
el-get: byte-compiling autoload file
Wrote /tmp/el-get-test-home/.emacs.d/el-get/.loaddefs.elc
el-get: evaluating autoload file
Loading ~/.emacs.d/el-get/.loaddefs...
require 'powerline
el-get initialized package powerline
el-get-reload: powerline
Loading /tmp/el-get-test-home/.emacs.d/el-get/powerline/powerline...
Loading /tmp/el-get-test-home/.emacs.d/el-get/powerline/powerline-separators...
Loading /tmp/el-get-test-home/.emacs.d/el-get/powerline/powerline-themes...
el-get-init: powerline
el-get-init: 
el-get initialized package cl-lib
require 'powerline
el-get initialized package powerline
el-get updated package powerline
powerline updated: This package has been updated successfully by el-get.
el-get update powerline
*** Update successful ***
el-get: updating autoloads for powerline
Generating autoloads for powerline/powerline-themes.el...
Generating autoloads for powerline/powerline-themes.el...done
Generating autoloads for powerline/powerline.el...
Generating autoloads for powerline/powerline.el...done
Saving file /tmp/el-get-test-home/.emacs.d/el-get/.loaddefs.el...
Wrote /tmp/el-get-test-home/.emacs.d/el-get/.loaddefs.el
(No changes need to be saved)
(No changes need to be saved)
el-get: byte-compiling autoload file
Wrote /tmp/el-get-test-home/.emacs.d/el-get/.loaddefs.elc
el-get: evaluating autoload file
Loading ~/.emacs.d/el-get/.loaddefs...
el-get removed package powerline
powerline removed: This package has been removed successfully by el-get.
el-get remove powerline
*** Removal successful ***
el-get-install powerline: (cl-lib powerline)
el-get-install-next-packages: cl-lib
el-get: `cl-lib' package is already installed
el-get-install-next-packages: powerline
Running commands synchronously: ((:command-name "*git clone powerline*" :buffer-name "*git clone powerline*" :default-directory "~/.emacs.d/el-get/" :program "/usr/bin/git" :args ("--no-pager" "clone" "http://github.com/milkypostman/powerline.git" "powerline") :message "Package powerline installed." :error "Could not install package powerline.") nil (:command-name "*git submodule update*" :buffer-name "*git clone powerline*" :default-directory "/tmp/el-get-test-home/.emacs.d/el-get/powerline/" :program "/usr/bin/git" :args ("--no-pager" "submodule" "update" "--init" "--recursive") :message "git submodule update ok" :error "Could not update git submodules"))
el-get is waiting for "*git clone powerline*" to complete
"Cloning into 'powerline'...
Checking connectivity... done
"
el-get: Package powerline installed.
Running commands synchronously: ((:command-name "*git submodule update*" :buffer-name "*git clone powerline*" :default-directory "/tmp/el-get-test-home/.emacs.d/el-get/powerline/" :program "/usr/bin/git" :args ("--no-pager" "submodule" "update" "--init" "--recursive") :message "git submodule update ok" :error "Could not update git submodules"))
el-get is waiting for "*git submodule update*" to complete
""
el-get: git submodule update ok
el-get: pakage powerline checksum is 6d62f7c6ad64dd734518ad451a1a7c8a5115fcb3.
el-get-build powerline
Running commands synchronously: ((:command-name "byte-compile" :buffer-name "*el-get-build: powerline*" :default-directory "/tmp/el-get-test-home/.emacs.d/el-get/powerline/" :shell t :stdin (:load-path ("." "/tmp/el-get-test-home/.emacs.d/el-get/powerline" "~/.emacs.d/el-get/" "/home/fgallina/Code/Projects/el-get/methods" "/home/fgallina/Code/Projects/el-get" "/usr/share/emacs/24.3/lisp" "/usr/share/emacs/24.3/lisp/vc" "/usr/share/emacs/24.3/lisp/url" "/usr/share/emacs/24.3/lisp/textmodes" "/usr/share/emacs/24.3/lisp/progmodes" "/usr/share/emacs/24.3/lisp/play" "/usr/share/emacs/24.3/lisp/org" "/usr/share/emacs/24.3/lisp/nxml" "/usr/share/emacs/24.3/lisp/net" "/usr/share/emacs/24.3/lisp/mh-e" "/usr/share/emacs/24.3/lisp/mail" "/usr/share/emacs/24.3/lisp/language" "/usr/share/emacs/24.3/lisp/international" "/usr/share/emacs/24.3/lisp/gnus" "/usr/share/emacs/24.3/lisp/eshell" "/usr/share/emacs/24.3/lisp/erc" "/usr/share/emacs/24.3/lisp/emulation" "/usr/share/emacs/24.3/lisp/emacs-lisp" "/usr/share/emacs/24.3/lisp/cedet" "/usr/share/emacs/24.3/lisp/calendar" "/usr/share/emacs/24.3/lisp/calc" "/usr/share/emacs/24.3/lisp/obsolete" "/usr/share/emacs/24.3/leim") :compile-files ("/tmp/el-get-test-home/.emacs.d/el-get/powerline") :clean-directory "/tmp/el-get-test-home/.emacs.d/el-get/powerline/") :sync t :program "/usr/bin/emacs" :args ("-Q" "-batch" "-f" "toggle-debug-on-error" "-l" "/home/fgallina/Code/Projects/el-get/el-get-byte-compile" "-f" "el-get-byte-compile-from-stdin") :message "el-get-build powerline: byte-compile ok." :error "el-get could not byte-compile powerline"))
el-get is waiting for "byte-compile" to complete
"Debug on Error enabled globally
el-get-byte-compile: Cleaning stale compiled files in /tmp/el-get-test-home/.emacs.d/el-get/powerline/
el-get-byte-compile: /tmp/el-get-test-home/.emacs.d/el-get/powerline
Checking /tmp/el-get-test-home/.emacs.d/el-get/powerline...
Compiling /tmp/el-get-test-home/.emacs.d/el-get/powerline/powerline-separators.el...
Wrote /tmp/el-get-test-home/.emacs.d/el-get/powerline/powerline-separators.elc
Compiling /tmp/el-get-test-home/.emacs.d/el-get/powerline/powerline-themes.el...
Wrote /tmp/el-get-test-home/.emacs.d/el-get/powerline/powerline-themes.elc
Compiling /tmp/el-get-test-home/.emacs.d/el-get/powerline/powerline.el...
Wrote /tmp/el-get-test-home/.emacs.d/el-get/powerline/powerline.elc
Done (Total of 3 files compiled)
"
el-get: el-get-build powerline: byte-compile ok.
el-get: updating autoloads for powerline
Generating autoloads for powerline/powerline.el...
Generating autoloads for powerline/powerline.el...done
Generating autoloads for powerline/powerline-themes.el...
Generating autoloads for powerline/powerline-themes.el...done
Generating autoloads for powerline/powerline-separators.el...
Generating autoloads for powerline/powerline-separators.el...done
Saving file /tmp/el-get-test-home/.emacs.d/el-get/.loaddefs.el...
Wrote /tmp/el-get-test-home/.emacs.d/el-get/.loaddefs.el
(No changes need to be saved)
el-get: byte-compiling autoload file
Wrote /tmp/el-get-test-home/.emacs.d/el-get/.loaddefs.elc
el-get: evaluating autoload file
Loading ~/.emacs.d/el-get/.loaddefs...
require 'powerline
el-get-install-next-packages: nil
el-get initialized package powerline
powerline installed: This package has been installed successfully by el-get.
el-get install powerline
el-get initialized package cl-lib
*** Second install successful ***
*** SUCCESS /home/fgallina/Code/Projects/el-get/recipes/powerline.rcp ***
```