Adding in CUSTOM_NOTIFICATION to contacts so that notification sounds can be assigned on a per contact basis rather than system wide.

Change-Id: I850eb7833adcf3f57fc363ea502381f8ceecc126
contacts: Privacy Guard support

 * If privacy guard is enabled for the calling process, return an empty
   MemoryCursor (with column names populated) instead of the real dataset.

Change-Id: I78b16f3791706636d51785e46a1f2ec656a3c9d2
Fix a typo.