Support Bitmap input to DataCardImage.

Support Bitmap input to DataCardImage by writing any Bitmap provided to
internal storage using a random identifier upon publish. A Content URI
is written to the database to represent the image. Add a ContentProvider
URI to return cached images. Implement logic to cleanup the cache
directory on update or delete, so that if any cached files are not
represented in the database, they are deleted. Change publish on all
PublishableCards to be asynchronous.

Change-Id: Ifad5fd3fa70d77590632e0b0b8e7541ba9cb14c7
Add resource support for DataCardImage.

Change-Id: Ie4e54a7b1b72c76bfae50cd718186d373ae49481