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
added some testing code to benchmark the heka-node client
Merge branch 'features/heka-stdliblogging' into features/heka-0.4.0

Conflicts:
	docs/source/api/encoders.rst
	docs/source/config.rst
	heka/encoders.py
	heka/tests/test_client.py