Proxy user model, make email optional.
Can't CC self if we don't have a key.
Error handling for users without keys or no explicit default key.
Some form cleanup.
Change encryption to avoid message size limits.

1. Generate random passphrase
2. Encrypt payload with random passphrase using AES
3. Encrypt passphrase with publickey using PKCS1_OAEP
4. Glue it together