NetworkSettings: Don't error out with TD-SCDMA values

This adds persistence and the ability to read TD-SCDMA values if
they are set. Both Network configuration and the QS tile toggle
now cycle these modes correctly
Devices supporting TD-SCDMA need to overlay the config_enabled_tdscdma
boolean configuration value to "true" for the proper network modes
to be presented to the user.

The ro.telephony.default_network should also be changed to a TD-SCDMA
value (20 or 18, depending on whether LTE is also supported)

Change-Id: I3a88a01aa9c5c111101c53388d5ba76a99cd0df6
Add TD-SCDMA UI support

Add TD-SCDMA PreferredNetwork display changes.
Add network mode TD-SCDMA to the list of
supported network modes.

Change-Id: Ib5adbf37e0fd3f17b64e64bc5b8a9d32e129af70
CRs-Fixed: 479310
(cherry picked from commit e0c7eba36ffcab551bddf9838f49278efec3f63b)
(cherry picked from commit be1bc56a5664bab05a896d8aebf808c07e946a44)
(cherry picked from commit 2275e2a28de775192675d7decbaf9d534bc312db)

Conflicts:
	src/com/android/phone/MobileNetworkSettings.java
Update Settings DB with correct Preferred NW mode

Introduction of mButtonEnabledNetworks preference does not ensure
the correct value of preferred network mode in Settings DB. So, the
User chosen mode does not retain. Both the preference objects are
handled properly to ensure right preferred network mode in the DB.

Change-Id: I35c4b231d5e61ac3efd71dd43b3a88a9ad9586fd
CRs-Fixed: 571980

Conflicts:
	src/com/android/phone/MobileNetworkSettings.java