escape html in messages

allow simple formatting later
simplify room exit cleanup

added benefit of using $routeChangeStart: checking for modified path
unnecessary
add "show more messages" button

scrolling is not perfect
add bbcode support to messages
separate room members and online users display

using filters to update user counters to avoid extra watches and
Object.keys() usage although it is not the perfect place to do so
remove unused, old code

logic no longer needed, similar functionality now present in Messaging
Controller
Merge pull request #16 from reebalazs/improve_messaging4

Improve messaging4