Iterator experiment
generators... so much faster, so much simpler
added iteration to sharding and cascading cache
added common backend test base class, fixed the bugs it found
added test for apc and memcache
fixed phpredis purging on setup
removed item deleting
fixed null/false return
fixed item deleting
fixed null/false bug
always return an array
keyBackend is optional
null/false return confusion
documentation
Improved testing and docs