Bug 1105857 - [Messages] User doesn't receive any notification about incoming message if native modal dialog is shown. r=schung

Just ask Bevis about the spec of class-0 message, but it just mentioned that MS shall
display the message immediately and send an acknowledgement to the SC when the message has successfully reached the MS irrespective of whether there is memory available in the (U)SIM or ME. Maybe we will need to display the latest message on the dialog and pop the message stack instead. I talked with Jenny as well and she prefers to keep the message and display the latest on the top. So maybe we will still need the queue(or stack) and flag for handling the old messages. Sorry I don't have any better idea for it :(