Changes to sclang-ac-modes

* Remove explicit call to 'run-hooks'. The function defined by 'define-minor-mode' already calls this, so it was being called twice.

* Add 'sclang-mode' to 'ac-modes' list.
Remove more doubled-up calls to 'run-hooks'
Resolves #4: Remove yasnippet ac source
Update to use Cask instead of Carton