Add dialog to show waiting for connection acceptance on the other peer device

[ekigamba]

Currently when one peer device accepts the connection and the other has not yet accepted the connection, the peer device will have the send and receive buttons disabled while nothing is shown. At this point it is waiting for the other peer device to either accept or reject the connection.

This does not communicate anything to the user and might seem confusing or as if the app has hang. Since it is not doing anything