add redis backend
pep8
add note about python25 strptime
add myself to AUTHORS
enable additional redis kwargs to be passed to backend
change date format to allow python25 support

add comments
Merge branch 'redis-backend' of github.com:ewheeler/cleaver into track-individual-participation

Conflicts:
	cleaver/backend/redis/backend.py
	cleaver/tests/backend/test_redis.py
	cleaver/tests/test_redis_stack.py
	cleaver/tests/test_sqlalchemy_stack.py