Updated Predis to work with 1.*, not 0.8

I'm not sure if you'll have any use for this or be interested in any of the changes, but these are changes I made to get SncRedisBundle working with Predis 1.0 -- take them or leave them. Tests look to be passing (with two failures that were present before the changes I've made.)
This class should implement `Predis\Connection\NodeConnectionInterface`.