Fixed reference to jquery-1.9.3 in /App/notifications-main.js
Updated client-side mentions regex, fixed bug when the user has no mentions set.
The users name is now included in mention strings if it doesn't already exist
Updated server-side mentions regex, minor cleanup of MentionExtractor
Removing username mentions without @ so there is less confusion, server-side doesn't support these for notifications yet.
Fixed username autocomplete