Design doc http://shortn/_GG690j15js
1. Modified SmsManager to send message thru Bluetooth if the subscription
is for a Remote-SIM.
2. Added new column 'subscriptionType' to SubscriptionInfo.
3. SubscriptionManager:
a. Added new constants for Local SIM and Remote SIM
b. Added hidden APIs to add/remove Remote SIM subscriptions
Bug: 112321331
Test: tested manually and w/ unittests
Change-Id: Ib15553a806691a258fc00f7aaf812b8a9d49c2e9