By catching the crash Signal remains unlocked. The user can quickly
retry sharing from the previous app and it will work, rather than
having to return to the home screen and unlock Signal.
Closes#5805
// FREEBIE
1) Move all the crypto classes from securesms.crypto.
2) Move all the crypto storage from securesms.database.keys
3) Replace the old imported BC code with spongycastle.
1) Update the create, prompt, and change passphrase activities.
They are no longer dialog themed, and should look a little
less ugly.
2) Update the import DB activity to be less ugly and more robust.
3) Abstract all of the state handling stuff out of
ConversationListActivity. This is now handled by RoutingActivity,
which all launch intents move through.
