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
Fixed typo in client.py
When line is not splittable, add to a __raw__ key
add from_url() classmethod to ConnectionPool and BlockingConnectionPool, add ability to parse UNIX domain socket URLs
* add redis.connection.parse_url()
  * moved code from StrictRedis.from_url() to here
  * add ability to parse UNIX domain socket URLs
  * return keyword args to pass to StrictRedis.__init__()
* StrictRedis.from_url() - call parse_url() to get keyword args
* add classmethod from_url() to ConnectionPool and BlockingConnectionPool
  * get keyword args from parse_url()
  * touch up keyword args from StrictRedis format for connection pool
* tests/test_connection_pool.py
  * add from_url() tests for ConnectionPool and BlockingConnectionPool
  * add from_url() tests for a single Redis client object
pep8 fixes
restore a feature that was inadvertently removed
* fixed parsing URLs without a scheme, e.g. "//localhost:6379"
Add scan_iter/sscan_iter/hscan_iter and zscan_iter
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
Fix for pep8
add SSL support
fix line too long (coding style test)