Fix failing test with undefined clientId

Small victories.
Remove useless connection logging
Don't destroy clients when publishing

Publishing was stepping on GC's toes by calling `destroyClient` whenever
it detected a client ID was past its prime. I *think* there may have
been some contention between the two (publisher and gc), so this moves
the cleanup responsibility wholly to the latter.

Well, not completely. The `disconnect` function inside of Faye itself
calls `destroyClient` as well, but let's leave that be.
Convert console.log to Faye debug in GC
Rewrite destroyClient to tolerate Redis failures

A lot of changes here. Primarily, the destroyClient function now
tolerates Redis failures all the way downstream, and if any error is
detected, the destroy process stops. Instead of trying to recover, we
rely on the hope that GC will pick up a client and re-run the calls in
the future, since the removal from the /clients sorted set is the final
Redis call.

The GC lock has also been removed. After grabbing a list of expired
client IDs, we iterate over them with destroyClient, which returns
immediately. Since we're simply launching destroyClient into flight, and
don't care if it succeeds or not, we allow GC to re-run in the future
without any restrictions.

Because destroyClient doesn't block, we have an additional, expected
test failure -- "Redis engine destroyClient when the client has
subscriptions stops the client receiving messages:". This will fail b/c
it's written to expect the destroy to occur immediately. If the test is
rewritten with the expectation in a callback, it succeeds.
Set the score with the initial ZADD in createClient

Previously, it would set the initial score to zero, and then allow
ping() to update the score to now in the callback. This seems like it
would allow a window of opportunity for GC to sneak in and kill the
newly created client, however, so now it simply sets the score in the
initial call.
Modify Faye logging level when running tests
Update README with test running instructions
Update version
Fixed namespace when removing subscriptions
Merge pull request #1 from groupme/redis-errors

Rewrite GC to handle Redis failures