Add tests for es#bulk; support index and type

Extensive tests for the es#bulk operation
Ability to pass use the endpoints /{index}/_bulk,
and {index}/{type}/_bulk by passing those parameters
in the options as _index and _type
Fixed the pulling out of the options arguments
when it is not defined (GH-62)
Merge pull request #69 from hmalphettes/bulk

Add tests for es#bulk; support index and type