Add SmartDial database for the Dialer app.

- Creates a database helper to create a smartdial database for the Dialer app.
- Queries all rows in the Contact database and copies related columns to
  the smart dial database.
- Create another prefix database to contain all prefixes of a contact.
- During keypad input, the prefix databse is queried to find contact
  suggestions, and suggestions are ranked by the usage data and contact
  status (starred, primary contact, etc.)
- Created unit test for the SmartDial database insertion and prefix
  computing functions.

Change-Id: I4d7c3b3bcc52dd6efa4d6e69d3f1687c3abaeb69