mozilla/MozStumbler — pull request #1138 by crankycoder (2014-10-28 15:29:34+00:00)
Title: 1137 - fix crash on tablets

Fix for #1137

* Default the signal strength and CDMA dbm to be UNKNOWN_SIGNAL
* if no telephony hardware is detected, the CellScannerImplementation::start() short circuits and doesn't enable any listeners
* stop() on the CellScannerImplementation will only unhook the listener if it's non-null and the telephony type is GSM or CDMA.