First pass at Interface refactor
Improve output of Makefile
Merge branch 'master' into new-interfaces

Conflicts:
	CHANGES
	Makefile
	src/sentry/interfaces.py
	src/sentry/manager.py
	src/sentry/models/event.py
	src/sentry/search/django/backend.py
	src/sentry/utils/safe.py
	tests/sentry/coreapi/tests.py
Maintain support for old-style exceptions
Update interface docstring to suggest passing as key