Document lack of order guarantees for BATCH statements

Patch by Tyler Hobbs, reviewed by Sylvain Lebresnse and Alex Popescu for
CASSANDRA-7123
Merge branch 'cassandra-2.0' into cassandra-2.1
Merge branch 'cassandra-2.1' into trunk
Add Google Compute Engine snitch.

Patch by Brian Lynch, reviewed by brandonwilliams for CASSANDRA-7132
Merge branch 'cassandra-2.0' into cassandra-2.1

Conflicts:
	CHANGES.txt
Merge branch 'cassandra-2.1' into trunk

Conflicts:
	CHANGES.txt
fix GCS test for 2.0
Merge branch 'cassandra-2.0' into cassandra-2.1
Merge branch 'cassandra-2.1' into trunk
Patched version of Disruptor Thrift Server

patch by Mikhail Stepura; reviewed by Brandon Williams for CASSANDRA-6545
Cleanup selector's keys.

patch by Mikhail Stepura; reviewed by Brandon Williams for CASSANDRA-6546
Merge branch 'cassandra-1.2' into cassandra-2.0

Conflicts:
	src/java/org/apache/cassandra/thrift/CustomTHsHaServer.java
Merge branch 'cassandra-2.0' into cassandra-2.1
Merge branch 'cassandra-2.1' into trunk
Parallel streaming for sstableloader

patch by Joshua Mckenzie; reviewed by yukim for CASSANDRA-3668
Merge branch 'cassandra-2.1' into trunk
Add Google Compute Engine snitch

Patch by Brian Lynch, reviewed by brandonwilliams for CASSANDRA-7132
Merge branch 'cassandra-1.2' into cassandra-2.0
Merge branch 'cassandra-2.0' into cassandra-2.1
Merge branch 'cassandra-2.1' into trunk