Make sure metadata points to UK resources
Added the CONTRIBUTING file
JCLOUDS-560: Removed references to an extension API in Glance.
JCLOUDS-614: Add Rackspace Auto Scale UK provider and update US regions
JCLOUDS-622 removed the deprecated Strings2.toString() method
Cleaned up the Glance v1 API and refactored expect tests
Prefer ByteStreams2 over ByteSources.asByteSource

The latter breaks the contract of ByteSource which specifies that
openStream can produce multiple independent streams.