added heka-py and heka-py-raven integration
added dependency on raven 3.4.1 and heka-py-raven 0.7
dropped all instances of the standard python logger for ichnaea
added heka logging tests for search
* removed unnecessary mangling of the heka_client in the heka_tween_factory
* removed unnecessary function call indirection
Merge pull request #57 from crankycoder/features/heka-py

added heka-py and heka-py-raven integration - refs #13, #14