prototype of Delete Multiple Objects API
Add ACL and policy check to each object at Delete Multiple Objects
Resouce on delete multiple objects changed to riak_cs_wm_bucket_delete
Fix unicode key name in delete multiple objects
Add python client test
Fix several bugs, strange but valid keys and non-existent buckets and keys
Fix boto test on delete multiple objects
Fix to please dialyzer
Fix bug on XML spaces and some comments
Merge pull request #899 from basho/feature/multi-delete

Feature/multi delete

Reviewed-by: shino