Avoid IAE in IndexSummaryManager while sorting sstables

Patch by Tyler Hobbs; reviewed by Benjamin Lerer for CASSANDRA-8182
Handle negative timestamps in writetime method

patch by slebresne; reviewed by thobbs for CASSANDRA-8139
Merge branch 'cassandra-2.0' into cassandra-2.1

Conflicts:
	CHANGES.txt
	src/java/org/apache/cassandra/cql3/UpdateParameters.java
Fix race in RecoveryManagerTest
patch by Sam Tunnicliffe; reviewed by jbellis for CASSANDRA-8176
Update CQLSSTableWriter to allow parallel writing of SSTables on the same table within the same JVM

Patch by Carl Yeksigian, reviewed by Benjamin Lerer for CASSANDRA-7463
Merge branch 'cassandra-2.0' into cassandra-2.1
Fix totalDiskSpaceUsed calculation

patch by yukim; reviewed by krummas for CASSANDRA-8205
Merge branch 'cassandra-2.0' into cassandra-2.1

Conflicts:
	CHANGES.txt
	src/java/org/apache/cassandra/io/sstable/SSTableDeletingTask.java
cqlsh: upgrade bundled python driver to 2.1.2

Patch by Tyler Hobbs for CASSANDRA-8031
Fix merge on test
fix test, take 2
add jmxPort to stress args (ninja)