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) Make the radio change a synchronous action with a timeout.
2) Move the send logic into an MmsTransport, in preparation for
UniversalTransport composition.
3) Move the download logic into a synchronous receiver.
