RFE: Support for recursive delete

From Openstack Swift point of view, feature to delete all objects in container at once may not be required.

But as gluster-swift is a RESTful front-end for glusterfs volume, a user should be able to delete a container that is not empty. As of now, this can be done easily (rm -rf) via Filesystem interface but NOT via RESTful interface.

To implement this, we can provide a header (may be X-Recursive-Delete) and a configurable option in conf file to enable recursive delete. Proposing to implement one or more of these tasks for icehouse release:
- Delete a non empty container and all objects in it
- Delete arbitrary paths like "AUTH_test/c1/d1/d2" which should delete files and directories under c1/d1/d2/*