Remove old references to plugins

See TryGhost/Ghost/2295
Compile SASS using node-sass

closes #5
- Added node-sass to package.json
- Added new grunt tasks to compile sass and copy fonts/css to dist
- Added new folders to .gitignore
- Added clean task
- Fixed README
Remove all %placeholder extends

* Allows us to use node-sass and drop the dependency on Ruby
* See TryGhost/Ghost/issues/1346
* See TryGhost/Ghost/issues/2078
Removing .modal-info

This is not used anywhere in ghost core
Removing disturbing mental image
Dat dist
Dist'in
Introducing bootstrap JS components as a starting point

Except carousel, cause dat shit cray.
Fix indentation
Comment/indentation cleanup
Fetch bourbon/breakpoint/normalize via bower

closes #14
- Fetch libraries via bower on `grunt`
- Use breakpoint 2.0.6 due to libsass failures
- Add grunt-shell to execute bower install
- Adjust screen.scss