Mentions are now separated into 'this room' and 'all rooms'
tab., which allows the user to filter on the current room
if they desire. Should add additional logic in the future
to show which room the mention was in the for the 'all rooms'
view.
Add a RoomListItem-like button that opens a dialog
containing all of the messages that would result in a
highlight from the server (for example, the user is mentioned,
or @room is mentioned).
This is VERY rudimentary and will be completely reworked in the future
to take advantage of the existing TimelineView class, instead of
using a dialog like it does now. The button to show the mentions
also needs work.
