Support nul/non-existant fields in UDT

patch by slebresne; reviewed by iamaleskey for CASSANDRA-7206
Correctly name FileCache metrics.

Patch by Nick Bailey, reviewed by brandonwilliams for CASSANDRA-7294
Merge branch 'cassandra-2.0' into cassandra-2.1
Merge branch 'cassandra-2.1' into trunk
Bump cqlsh default CQL version to 3.1.7

Follow up for CASSANDRA-6875
Merge branch 'cassandra-2.1' into trunk
fix merge-created bad map key lookup type
Merge branch 'cassandra-2.1' into trunk
fix countAllBatches query
patch by Lyuben Todorov; reviewed by jbellis for CASSANDRA-7300
Merge branch 'cassandra-2.1' into trunk
cqlsh: always emphasize the partition key in DESC output

patch by Patrick McFadin; reviewed by Aleksey Yeschenko for
CASSANDRA-7274
Merge branch 'cassandra-2.0' into cassandra-2.1

Conflicts:
	CHANGES.txt
	bin/cqlsh
Merge branch 'cassandra-2.1' into trunk
Properly decode UDTs with nulls in cqlsh

patch by Mikhail Stepura; reviewed by Aleksey Yeschenko for CASSANDRA-7289
Merge branch 'cassandra-2.1' into trunk
don't NPE shutting down, due to gossip failure
Merge branch 'cassandra-2.0' into cassandra-2.1
Merge branch 'cassandra-2.1' into trunk
Make parallel repairs default (needed to make incremental repairs work)

Patch by marcuse; reviewed by jbellis for CASSANDRA-7250
Copy compaction options to make sure they are reloaded.

Patch by pauloricardomg; reviewed by marcuse for CASSANDRA-7290