helm.rcp: fix build on OS X.

By override the EMACS_COMMAND in the Makefile of helm.
Fix emacs-jabber for OSX
Fix sclang-snippets :depends
change sunrise-commander.rcp to :type github
change rainbow-mode to :type github
Add ac-ghc-mod
Add :prepare blocks for some recipes

* recipes/hi2.rcp,
* recipes/hideshow-org.rcp,
* recipes/highline.rcp,
* recipes/rainbow-mode.rcp,
* recipes/workgroups2.rcp,
* recipes/yank-pop-summary.rcp,
* recipes/zencoding-mode.rcp: Add autoloads and/or foo-mode-on functions
  in :prepare block.
Merge pull request #1998 from npostavs/pitometsu-1899

Add hooks for some recipes (1899) v2
Update package.el git revision hash

Following Emacs' transition to git, the hashes of commits have changed
because some commits were edited to remove bzr specific
referefences (e.g. revnos in commit messages).

Note: the equivalent bzr commit had revno 103620 on trunk, revid
cyd@stupidchicken.com-20110310234046-vzsm4s3pjxc1aids.

First line of commit: "Fix package.el handling of version numbers like
1.0pre6"

* recipes/package.rcp (package):
* test/travis-ci.sh: Update hash for last package.el version compatible
  with Emacs 23.
Add dependency on `f` to `projectile` recipe

A recent version [1] of `projectile` depends on the `f` package.

[1] https://github.com/bbatsov/projectile/blob/7f483c525987785716e22f0b364eb6be683a0bbc/projectile.el#L41
el-get-sources: deduplicate :pkgname in docstring
Take sha1 of buffer contents, not buffer

This prevents the sha1 function from attempting and then failing to
encode the buffer contents in the wrong encoding.

* methods/el-get-http.el (el-get-http-compute-checksum): Call `sha1' on
  result of `buffer-string', not `current-buffer'.
Add rails-new.
Fix foo-mode-on functions descriptions in :prepare
Add :prepare blocks for some recipes

Add autoloads and/or foo-mode-on functions
 in :prepare block for:

- recipes/ace-jump-mode.rcp
- recipes/auto-indent-mode.rcp
- recipes/pp-c-l.rcp
- recipes/window-number.rcp
- recipes/windsize.rcp
Merge pull request #2003 from Pitometsu/pitometsu

Add :prepare blocks for yet more recipes
Update python.el recipes to point to the GNU Emacs repo
install npostavs/current branch
el-get-reload: use unload-feature