Add aurora-config-mode

Major mode for editing Apache Aurora configuration files.  It's derived from
Python mode adding a Aurora and Pystachio helpers, structs and types along
with inspection commands.

Repository is at https://github.com/bdd/aurora-config.el
I am the maintainer of the package.

Tested build and installation.
```
 • Building recipe aurora-config-mode ...
/usr/local/opt/emacs/bin/emacs --no-site-file --batch -l package-build.el --eval "(let ((package-build-stable nil) (package-build-archive-dir (expand-file-name \"./packages\" pb/this-dir))) (package-build-archive 'aurora-config-mode))"

;;; aurora-config-mode

Fetcher: github
Source: bdd/aurora-config.el

Cloning git://github.com/bdd/aurora-config.el.git to /[redacted]/melpa/working/aurora-config-mode/
Loading vc-git...
Saving file /[redacted]/scratch/melpa/packages/aurora-config-mode-20140520.22.el...
Wrote /[redacted]/melpa/packages/aurora-config-mode-20140520.22.el
Wrote /[redacted]/melpa/packages/aurora-config-mode-readme.txt
File: /[redacted]/melpa/packages/aurora-config-mode-20140520.22.entry
Built in 0.064s, finished at Tue May 20 00:27:23 2014
 ✓ Wrote 8 -rw-r--r--  1 [redacted]  staff   3.6K May 20 00:27 ./packages/aurora-config-mode-20140520.22.el
8 -rw-r--r--  1 [redacted]  staff   194B May 20 00:27 ./packages/aurora-config-mode-20140520.22.entry
8 -rw-r--r--  1 [redacted]  staff   494B May 20 00:27 ./packages/aurora-config-mode-readme.txt
 Sleeping for 0 ...
sleep 0
```