This breaks backward compatibility for the wire protocol and messages
stored in the database. The database schema version has been
incremented.

Android L requires executables to be compiled with PIE support, so we'll
have to ship two Tor binaries.

Of course, not all devices support Bluetooth...

See
https://developer.android.com/guide/topics/ui/notifiers/notifications.html#NotificationResponse

This makes the contact list behave how alpha testers expected: touching
a contact shows private messages exchanged with the contact.

Some Android devices require a lock to be held while using multicast, to
disable the packet filter that normally filters out multicast packets.