documentation cleanups
dropped the header encoding and updated the compiled protobuf module
updated all tests to use protobuf encoding instead of JSON which is no
longer supported
* updated documentation to reflect the removal of JSON encoding
* updated docs to show change of StdlibJSONEncoder to StdlibPayloadEncoder
added some testing code to benchmark the heka-node client
removed header encoding from test helper
issue #16 -repoint README to use heka-docs.rtfd.org instead of sagrada wiki page
updated date on the release for 0.30.2