Fix JCLOUDS-250 for the common case where blob names do not contain /
Use constant for ETag header name
Avoid 'java.io.IOException: Unrecognized character: "' when a quoted ETag is encountered

This happens when getting a multipart blob from Rackspace Cloud.
Merge branch 'handle_quoted_etags' into bright
Merge branch 'JCLOUDS-250' into bright