Add basic mention functionality

Conflicts:
	lineman/app/js/services/restful_service.coffee
	lineman/app/templates/add_comment.haml
Add basic mention functionality
Merge pull request #1744 from loomio/angular-mentions

Add basic mention functionality
Fix comment form for mentions
meh
Merge branch 'angular' of github.com:loomio/loomio into angular
Merge branch 'angular' into angular-delete-comment
destroying comment is synched across all clients, along with create and update