Dynamically set the URI for the ContentProvider.

Between all extensions, the ContentProviders must be unique. In order to
make sure that they are unique, dynamically set the URI for
CmHomeContentProvider to be equal to "<package-name>.cmhomeapi"

Change-Id: Ifea5cf06d80c78d6074c1e6cc5909569a65d21e6
Improve how single rows are accessed.

Previously I was storing row IDs as ints, which was not correct.
Instead, use long. Also, to update/delete/query a single row, use the
Content URI that includes the ID to simplify access and make sure
observers are notified. Finally, a tiny bit of import/constants cleanup.

Change-Id: Ied3ad21b196dffa657e5d819653a8fcf318ff43d