Fix IRE with ORDER BY, treating all selections as fns

Patch by Tyler Hobbs; reviewed by Benjamin Lerer for CASSANDRA-8286
Merge branch 'cassandra-2.0' into cassandra-2.1
Fix multicolumn relation + COMPACT STORAGE issues

Patch by Tyler Hobbs; reviewed by Benjamin Lerer for CASSANDRA-8264
Merge branch 'cassandra-2.0' into cassandra-2.1
Fix CONTAINS (KEY) filtering on frozen collection clustering cols

Patch by Tyler Hobbs; reviewed by Benjamin Lerer for CASSANDRA-8302