native client: support Refresh requests

References #20
Refer to fewer functions
Cosmetics
wording
link to clojurewerkz.org
Switch to ElasticSearch master snapshot because of massive API breakages in the client
ignore Leiningen auxilliary files
Native client: implement Count and Delete actions, adapt to ES master changes

We will track ES master snapshots until the API changes around *Request and *Response
methods stabilize.

[ci skip]