Support multi-row selects within a partition using IN

Patch by Tyler Hobbs; review by Sylvain Lebresne for CASSANDRA-6875
Bump CQL version to 3.1.7, update CQL docs

Follow up for CASSANDRA-6875
Correctly name FileCache metrics.

Patch by Nick Bailey, reviewed by brandonwilliams for CASSANDRA-7294
cqlsh: always emphasize the partition key in DESC output

patch by Patrick McFadin; reviewed by Aleksey Yeschenko for
CASSANDRA-7274
don't NPE shutting down, due to gossip failure
Copy compaction options to make sure they are reloaded.

Patch by pauloricardomg; reviewed by marcuse for CASSANDRA-7290
Add option to do more aggressive tombstone compaction.

Patch by pauloricardomg; reviewed by marcuse for CASSANDRA-6563
fix typo
Merge branch 'cassandra-1.2' into cassandra-2.0

Conflicts:
	src/java/org/apache/cassandra/service/StorageService.java
Make sure we don't try to compact already compacting sstables in HHOM

Patch by marcuse; reviewed by jbellis for CASSANDRA-7288
xmx
explain how to specify a keyspace
add src/resources to the generate eclipse .project file's src paths

patch by opeer reviewed by dbrosius for cassandra-5964
Use HadoopCompat to get job context
Patch by Ben Coverston, reviewed by brandonwilliams for CASSANDRA-7315
remove duplicate changes entry
Add authentication support to shuffle

patch by Aleksey Yeschenko; reviewed by Brandon Williams for
CASSANDRA-6484
CHANGES.txt whitespace
Merge branch 'cassandra-1.2' into cassandra-2.0

Conflicts:
	CHANGES.txt
Ninja: remove redundant check for null
Ninja: use equals() for Boolean comparison