holoirc: add UI side of the noticiation settings
holoirc: add vibrate option as well
holoirc: add sharedprefs side of code for notification settings
holoirc: split off mention handling into a separate utility class
holoirc: actually handle the notification settings
holoirc: fix up the final things to make all the notification stuff work properly
Merge branch 'feature-notifications' into develop