Merge pull request #10 from mozilla-services/dev

Patches to make heka-py play nicely with heka 0.3
moved heka.senders.logging to heka.streams.logging
added a new StdlibJSONEncoder which prefixes the JSONEncoder output with a single byte denoting the stdlib logging log level that should be used.
build_sender now allows you to use strings or actual factory functions to create an encoder instance.
Simplified the mapping of stdlib logging's log levels to syslog log levels by using a map.  Added the original stdlib logging log level as a field in the call to heka()
Updated testcases during the rename of StdlibLoggingSender to StdlibLoggingStream and the new StdlibJSONEncoder.
removed all instances of heka.senders from tests and code
Updated all tests to work without heka.senders namespace
dropped pyzmq dependency
- bumped revision to 0.30.2
- removed all pyzmq and zeromq references
- updated documentation to remove references to `heka.senders`
  namespace
Merge branch 'dev' into features/heka-stdliblogging

Conflicts:
	CHANGES.rst
weakened the testcase that samples messages
added NullEncoder to pass messages untouhced into the HekaClient instance
added a LOGLEVEL_MAP to compute log levels given a severity level
dropped the NoSendSender
added documentation for all streams, encoders and example for each.
added example configuration for all stream types and added example
code for each stream output.
Updated docs to include more details for each encoder type
merged in the StdlibPayloadEncoder from features/heka-0.4.0 to better
match existing metlog/logstash functionality
Merge branch 'dev' into features/heka-stdliblogging

Conflicts:
	heka/tests/test_client.py