Validate token() args are in partition key order

Patch by Benjamin Lerer; reviewed by Tyler Hobbs for CASSANDRA-6075
Merge branch 'cassandra-2.0' into cassandra-2.1
Validate token() args are in partition key order

Patch by Benjamin Lerer; reviewed by Tyler Hobbs for CASSANDRA-6075
Merge branch 'cassandra-2.1' into trunk