Samsung STK: Add USSD support

Allow USSD-based STK applications to work

Change-Id: I483f37a44a6c3ed43eefcf979e17b84877d03f93

Conflicts:
	src/java/com/android/internal/telephony/cat/CatService.java
Samsung STK: Fix SMS-based STK

SEND_SMS was falling through to SEND_USSD (which used to do nothing
until USSD support was added) causing an Exception because cmdParams
is not an instance of SendUSSDParams.

Fix by using type-checking instead of checking if Samsung STK is
enabled (because SendSMSParams and SendUSSDParams will only be
created if Samsung STK is enabled.)

Change-Id: I671014e295e9e529aad25a8b6fbd5a2e5788fc44
Add initial preferred APN feature

Add new column "preferred" to the carriers database fot the initial
preferred APN setting.

Change-Id: Ife93851f29ee9cc24a1192281d49cd321e7638c6
Telephony: prevent NPE

Change-Id: Ia7a08334a901ef67353d5816d0822d0cb2d57daf
Telephony: check if the provisioning apn is actually empty before

checking if they are equal.  Fixes cases where the stubbed apn
(empty) equal to the empty provisioning apn.

Fixes no IP issues on CDMA data types.

Change-Id: Id7bda83778f5ce59c87463c4d44fc5768dbc4a08