added Boost, Credo & Ting APNs

Also changed name of Sprint MMS apn to be clearer.

Change-Id: Iba70c5882d0c65bc25ebfbf25018739eb800d160
add Virgin Mobile USA apn

Change-Id: Ia016e19b14a173746fddbc5319fac98ca9f188c5
Merge remote-tracking branch 'cm/cm-11.0' into cm-11.0