Replace UnsortedColumns usage with ArrayBackedSortedColumns

patch by Aleksey Yeschenko; reviewed by Sylvain Lebresne for
CASSANDRA-6630
update stream-lib for HLL++ serialization thread-safety
naming
Actually remove UnsortedColumns (CASSANDRA-6630 followup)
Correctly handle null in conditions with TTL

patch by slebresne; reviewed by iamaleksey for CASSANDRA-6623
Merge branch 'cassandra-2.0' into trunk

Conflicts:
	src/java/org/apache/cassandra/cql3/statements/ModificationStatement.java
	src/java/org/apache/cassandra/service/StorageProxy.java
Account for range and row tombstones in tombstone drop time histogram.

Patch by marcuse, reviewed by jbellis for CASSANDRA-6522
Merge branch 'cassandra-2.0' into trunk

Conflicts:
	src/java/org/apache/cassandra/db/ColumnFamily.java
	src/java/org/apache/cassandra/tools/SSTableMetadataViewer.java
Make it possible to cache a configurable amount of rows in row cache.

Patch by pcmanus and marcuse, reviewed by pcmanus for CASSANDRA-5357
Expose bulk loading progress over JMX
patch by Tyler Hobbs; reviewed by Nick Bailey for CASSANDRA-4757
Merge branch 'cassandra-2.0' into trunk
Improve nodetool cfhistograms formatting
patch by Tyler Hobbs; reviewed by Benedict Elliott Smith for CASSANDRA-6360
Merge branch 'cassandra-2.0' into trunk
Fix upgradesstables NPE for non-CF-based indexes
patch by Sergio Bossa; reviewed by jbellis for CASSANDRA-6645
merge from 2.0
Fix upgradesstables NPE for non-CF-based indexes
patch by Sergio Bossa; reviewed by jbellis for CASSANDRA-6645
merge from 1.2
merge from 2.0
Merge remote-tracking branch 'origin/cassandra-2.0' into cassandra-2.0
merge