elasticsearch path components (eg doc id) should be url quoted
add test for quoted chars in url
Clarify the meaning of "mapping" in docs.

Adrian thought I was referring to ES mappings rather than Python mappings.
Fix bulk indexing endpoint

The /{index}/_bulk endpoint wasn't added until ES 0.18.0:

https://github.com/elasticsearch/elasticsearch/issues/1375

This fixes pyelasticsearch so that it uses /_bulk as the endpoint
and thus works with versions of ES prior to 0.18.0.
Fix indentation from before I shortened the _send_request method name.
Make bulk indexing work on ES < 0.18. Fixes #59.
Add Will Kahn-Greene to AUTHORS
URL-escape path components, like doc IDs. Fixes #55.
Add willkg to AUTHORS. Fixes #61.
add cluster_state API
Make `es_kwargs` support a placeholder for methods that don't have any normal args to document.

Remove placeholder `query_params` arg from `cluster_state`.
Add cluster_state method.