Call blocker for spam blocking of calls.

Spam blocking:
* Spam blocking for calls by adding phone numbers to the blacklist.
* Block everyone except contacts.
* Block phone numbers by using area code.
* Block private numbers.
* Whitelist for phone numbers that should never be blocked.
* Calls blocking log.
* Quick search for blocked calls and phone numbers in the blacklist.
* Ability to turn call blocking on or off.