Support non-equals conditions for LWT

Patch by Tyler Hobbs; review by Sylvain Lebresne for CASSANDRA-6839
Merge branch 'cassandra-2.1' into trunk
UDF cleanups

patch by slebresne; reviewed by thobbs for CASSANDRA-7809
Add syntax to remove multiple elements from a map

patch by blerer & slebresne; reviewed by iamaleksey for CASSANDRA-6599
Merge branch 'cassandra-2.1' into trunk
Track expired tombstones

Patch by marcuse; reviewed by slebresne for CASSANDRA-7810
Merge branch 'cassandra-1.2' into cassandra-2.0

Conflicts:
	CHANGES.txt
	src/java/org/apache/cassandra/db/ColumnIndex.java
Merge branch 'cassandra-2.0' into cassandra-2.1.0

Conflicts:
	CHANGES.txt
Merge branch 'cassandra-2.1.0' into cassandra-2.1
Merge branch 'cassandra-2.1' into trunk
Avoid recycling CL segments until all writes have been flushed for all keyspaces in segment

Patch by belliottsmith; reviewed by tjake for CASSANDRA-7437
Merge branch 'cassandra-2.1.0' into cassandra-2.1
Merge branch 'cassandra-2.1' into trunk
Add ability to detect unofficial openjdk builds.

Patch by brandonwilliams, reviewed by enigmacurry for CASSANDRA-7799
Merge branch 'cassandra-2.0' into cassandra-2.1
Add ability to detect unofficial openjdk builds.

Patch by brandonwilliams, reviewed by enigmacurry for CASSANDRA-7799
Ninja s/substract/subtract
Merge branch 'cassandra-2.1' into trunk
Fix failure to stream ranges when moving

Patch by Tyler Hobbs; reviewed by Yuki Morishita for CASSANDRA-7836
Merge branch 'cassandra-2.1.0' into cassandra-2.1