v2.2.0

Edit and delete messages.

• Edit a message you sent: hold it, pick Edit, fix the text and send. It updates on the other phone too and is marked "edited".
• Delete for everyone: hold your own message and pick Delete for everyone; it turns into a grey "Deleted" on both phones. Delete for me does the same only on this phone.
• Scrolling fixes: reading older messages no longer jumps you back to the bottom when a new one arrives, and the jump-to-latest badge now shows the right count.

Both phones need this version for edits and deletes to reach the other side; an older phone simply keeps the original.