Add per-CF range read request latency metrics

patch by Sam Tunnicliffe; reviewed by Aleksey Yeschenko for
CASSANDRA-7338
Merge branch 'cassandra-2.0' into cassandra-2.1

Conflicts:
	CHANGES.txt
	src/java/org/apache/cassandra/db/ColumnFamilyStore.java
	src/java/org/apache/cassandra/metrics/ColumnFamilyMetrics.java
Merge branch 'cassandra-2.1' into trunk
cleanup
Merge branch 'cassandra-2.0' into cassandra-2.1
Merge branch 'cassandra-2.1' into trunk
close segments in resetUnsafe
patch by Ala' Alkhaldi; reviewed by Joshua McKenzie for CASSANDRA-7334
Merge branch 'cassandra-2.1' into trunk
Reduce run time for CQL tests

patch by slebresne; reviewed by thobbs for CASSANDRA-7327
Merge branch 'cassandra-2.1' into trunk
Fix heap size calculation on Windows
patch by Josh McKenzie; reviewed by Philip Thompson for CASSANDRA-7352
Merge branch 'cassandra-2.1' into trunk
RefCount native frames from netty to avoid corruption bugs

patch by tjake; reviewed by bes for CASSANDRA-7245
Merge branch 'cassandra-2.1' into trunk

Conflicts:
	src/java/org/apache/cassandra/transport/CBUtil.java
initial rip-out