[JCLOUD 301]: Make increased use of Invokable params cache

This patch moves the Invokable Parameter cache to Reflection2 and adds
a convenience method for it to allow it to be shared by multiple
callers. The subsequent ability of S3Utils to use this cache results
in a ~40% improvement in performance for generating signed GETs and
PUTs for S3. This commit also converts a few others calls to
Invokable.getParameters() but the observed benefit from those was
small in microbenchmarks.
Renamed variable and method more appropriately.
Fixed imports and formatting.
Added Marconi (Queues) to accessRackspace.
Reauthenticate on Keystone HTTP 401 (JCLOUDS-178)

The number of retries here is not the same as for 500 errors; expected
behavior is a quick fail while retaining some robustness.  This fix
should not reintroduce JCLOUDS-231.
JCLOUDS-334: Return false if container exists in AWS-S3

Works around S3 bug (or stale documentation).