Previously, SQLCipher's memory usage would grow indefinitely, up until
it hit the end of the cursor. We've now switched to a release where the
memory used by the cursor can be bounded.
The "contact" option in the attachments tray now brings you through an
optimized contact sharing flow, allowing you to select specific fields
to share. The contact is then presented as a special message type,
allowing you to interact with the card to add the contact to your system
contacts, invite them to signal, initiate a signal message, etc.
