added raven dependency explicity into the dependency file
moved the exception handling code into the tween for heka+raven logging
added heka configuration information to deploy.rst
pep8 fixes and changed some assert statements to use self.assertTrue
as per review
Merge commit 'f1de62a3181f7e150e4a75eff029c6826d8857ed' into features/heka-py-raven

Conflicts:
	ichnaea/content/tests/test_views.py
	ichnaea/heka_logging.py
	ichnaea/tests/base.py
	requirements/prod.txt
Merge remote-tracking branch 'crankycoder/features/heka-py-raven'
fix minor nitpicks, refs #71