Bug 970212 - B2G Emulator: Enhance GSM/UMTS Signal Strength on Emulator. r=Vicamo.

Trigger amodem_unsol_buffered to send RIL_UNSOL_SIGNAL_STRENGTH after
"gsm signal" command to update signal strength on status bar promptly.
Merge pull request #56 from chenghuk/master

Bug 970212 - B2G Emulator: Enhance GSM/UMTS Signal Strength on Emulator.