Use passport for authentification + twitter oauth

Now we can connect using twitter.
Add auth provider : google, facebook and local

Refactor the AuthController method, the only differences where the
provider name and the scope, get them as variable.

Simplify the routes accordingly.

Use the req.user as passport handle the serialization / deserialization
for us.
Authentification done.

Update the dev workflow : no grunt in sails lift,
assets are managed by grunt, workflow is :
 - change
 - clean
 - browserify / sass depending on the changed file
Merge branch 'oauth'
Change all build workflow. Use sass and browserify
Setup dev env properly
Merge branch 'feature/auth'

Conflicts:
	.gitignore
	assets/styles/main.scss
	tasks/config/clean.js
	tasks/config/copy.js
	tasks/register/default.js
Get the style back, purge www
Merge branch 'master' of github.com:ling-apps/hand-strat