Adds support for Rackspace Cloud Files API

This PR adds initial support for the Rackspace Cloud Files API. There are many changes in this PR and will address comments immediately. Thanks.  

JIRA: 
https://issues.apache.org/jira/browse/JCLOUDS-423

Additions:
  - Added support for CloudFilesApi/CDNApi
  - Added mock/live tests
  - Refactored listFirstPage() and listAt() API methods to list() and listWithOptions(…)
  - General Swift API cleanup: docs and tests
  - Added support for Internal URL

Command to run live tests:
mvn clean install -Plive -Dtest.rackspace-cloudfiles.identity=<username> -Dtest.rackspace-cloudfiles.credential=<password> -Dtest.rackspace-cloudfiles.endpoint=https://identity.api.rackspacecloud.com/v2.0 

To test a specific region, add “-Dtest.jclouds.region=<regionId>” to the above command.

Tested against various Rackspace Cloud Files US regions.

Caveats:
- BlobStore Live/Integration Test Failures - under investigation.
- CloudFiles US provider lacking BlobStore integration tests until above failures are addressed.
- Temporarily removed Static Web feature awaiting documentation clarification.
- JavaDocs can always use more attention/love.