Use standard lager for logs of "make test-client"
Merge pull request #898 from basho/refactor/use-lager-in-ext-client-test

Use standard lager for logs of "make test-client"

Reviewed-by: kuenishi
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