Mms: add blacklist functionality

Taken from the patch for the Phone app.

Original code written for CM7 by Cytown, Cyanogen and nhnt11.

Modified for CM10.1 by Danny Baumann and dvtonder.

Adapted for the MMS app by jt1134.

Change-Id: Ie229c31fbac3f6b9cb311664c446228e0aaae588