Allow admin to choose address type as Visiting or Postal. Assign type Visiting to all primary addresses.

Add tests for address types

Fix tests for addresses. Change json API to match new types.

Fix tests for addresses

Refactor addresses code

Fix address types tests. Use DatabaseCleaner truncation for reliable tests.
Merge pull request #50 from ministryofjustice/addresses

CF-135 Allow admin to choose address type as Visiting or Postal.