Adds a Statement class that can interpolate CQL variables
Switches executor to cql-rb

* cql-rb plays more nicely with recent versions of cassandra
* cql 3.1 is required now
* small (though breaking) API changes to conform better to cassandra 2.0
Fixes up some busted tests and includes gems that were missing
Restores fail fast option
Removes debugging "pry"
Merge branch 'cqlrb'