Track TwoWayView API changes.
Use L's new notification features.

Namely set notification color, priority, category and generate a public
version of the notification. Also ensure big text content has 2 lines,
as otherwise the notification can't be expanded on L, and use default flags
for sound and vibration + high priority to make query/mention notifications
eligible for heads-up.
Use min priority for the connection notifications to keep it out of L's
lock screen and the status bar.
Merge pull request #106 from maniac103/l-notif-fixes

L notif fixes