Simplify publish date checks

Fixes #814

- Changed to compare instances of `moment` using it's built in
comparison function instead of string compare with the date from the
database.
- Ensure compared date is parsed with the correct formats that we were
supporting before #1107.
- Moved date formats to variables to reduce chance for error in future.
Store the Bookshelf instance on the Bookshelf module

- Assigns the ghostBookshelf instance to the Bookshelf.ghost property
Issue/1007: Corrected the behaviour of the HOME and END keys on the CodeMirror editor by overriding their calls in the extraKeys config of the editor
Replace new-lines with spaces in excerpt helper.

fixes #531
Add core/server.js to grunt watch
Explicitly add Ruby dependencies to project via Bundler

closes #1220
- This uses Bundler to install Ruby dependencies to handle explicit
  dependencies in provisioned environments
- The initial Gemfile contains SASS dependencies (sass and bourbon gems)
State that Bourbon files are generated in CONTRIBUTING guide

Fixes #1255.
- This says that the Bourbon directory is generated and does not
  ambiguiate with the installation of the bourbon gem
Fix duplication of entries in infinite scroll

Fixes #1242

- Switched to render each new item as its added to the collection when
retrieving via scroll checks.
- Added check to remove all subviews whenever `render` is called on
`ContentList` as a preventative measure.
- Cached the jquery reference to the ordered list in `render`.
Only show notifications when logged in.

fixes #943
Merge pull request #1256 from mduvall/contributing-fix-for-bourbon

State that Bourbon files are generated in CONTRIBUTING guide
Merge pull request #1220 from mduvall/ruby-dependencies

Explicitly add Ruby dependencies to project
Merge pull request #1254 from halfdan/943-login-notification

Only show notifications when logged in.
Move /api to /ghost/api

closes #1249
- changed routes
- changed apiRoots
Allow only images to be uploaded in the upload modal

Fixes #1221

- This changes the accepted encodings on the files upload input field to
  be only "image/*" now
-
Merge pull request #1222 from mduvall/encoding-image-upload

r# the commit.
Merge pull request #1253 from halfdan/gruntfile-watch

Add core/server.js to grunt watch
Merge pull request #1245 from StevenMcD/issue/1007

Issue/1007: Corrected the behaviour of the HOME and END keys on the Code...
Merge pull request #1252 from halfdan/531-lines-to-spaces

Replace new-lines with spaces in excerpt helper.
Keep style consistent
Merge pull request #1251 from sebgie/api-refactor-move

Move /api to /ghost/api