Messages sent while disconnected disappear

Steps

1. Connect to core
2. Open buffer
3. Enable airplane mode
4. Send a message
5. Check input history

Expected

Messages aren't allowed to send while offline.

Or...

Message shows up in input history, letting you re-send it after reconnecting if needed.

Actual

Message disappears into the æther, never to be seen again, and doesn't show in the input history.

Additional

This is a quick fix to reduce the aggravation until a full-feature queuing/saving implementation can be implemented. It'll be less likely to encounter this when the client warns of disconnect inside UI, but it's still important in case the full composer is shown or the disconnect happens moments before sending.

Higher priority as this is a form of data loss.