refactored pubsub. needs tests
Merge branch 'master' into pubsub
if (p)unsubscribing from all channels, remember to empty to channel cache. fixes #274
change "suppress" to "ignore"
use a property to control the pubsub listen/thread loop
now that we have better control of the listen loop, we don't need to release the connection when all channels are unsubscribed. fixes #284 and #275
unnecessary connection disconnects
make sure hiredis parser raises connection errors
changelog
Adjust to changed TTL, PTTL semantics

Redis >= 2.8 might return -2, this ensures that redis-py just returns
None.
Merge branch 'master' into pubsub

Conflicts:
	redis/connection.py
fixed a bunch get_message() bugs, refactored the PythonParser to be saner.

still need more pubsub tests but all this stuff *seems* to be working now
make sure we're not holding onto any references
fixes PubSub.subscribe once and for all.
make sure we know the order of expected subscribe/unsubscribe messages
fix pep8 environment, explicit python versions and require pytest>=2.5
require pytest>=2.5 when running tests from setup.py
DEBUG LOADING was released in 2.8.8, so skip test with earlier versions
automatic message decoding if decode_responses=True. bugfixes, tests.
pubsub docs