Add paranoid disk failure option.

Patch by marcuse, reviewed by kohlisankalp and jbellis for CASSANDRA-6646
Improve PerRowSecondaryIndex performance

patch by Sergio Bossa; reviewed by Aleksey Yeschenko for CASSANDRA-6876
Add support for DELETE ... IF EXISTS to CQL3

Patch by Tyler Hobbs, reviewed by Sylvain Lebresne for CASSANDRA-5708
Extend triggers to support CAS updates

patch by Sam Tunnicliffe; reviewed by Aleksey Yeschenko for
CASSANDRA-6882
Pick unused generations when loading new sstables

patch by Tyler Hobbs; reviewed by Jonathan Ellis for CASSANDRA-6514
Include correct consistencyLevel in LWT timeout
patch by Sankalp Kohli; reviewed by jbellis for CASSANDRA-6884
Omit tombstones from schema digests
patch by Oleg Anastasyev; reviewed by jbellis for CASSANDRA-6862
Static columns with IF NOT EXISTS don't always work as expected

patch by slebresne; reviewed by iamaleksey for CASSANDRA-6783
Extend limits.conf in debian packaging.

Patch by brandonwilliams for CASSANDRA-6104
Merge branch 'cassandra-1.2' into cassandra-2.0
Add UNLOGGED, COUNTER options to BATCH docs

patch by Tyler Hobbs; reviewed by Sylvain Lebresne for CASSANDRA-6816
Add uuid() function
patch by Carl Yeksigian; reviewed by jbellis for CASSANDRA-6473
Merge branch 'cassandra-1.2' into cassandra-2.0

Conflicts:
	CHANGES.txt
comment CqlRow for #6807
Merge branch 'cassandra-1.2' into cassandra-2.0
CASSANDRA-6876 follow-up
Add CqlRecordReader to take advantage of native CQL pagination

patch by alexliu68; reviewed by pkolaczk for CASSANDRA-6311
Fix paging with SELECT DISTINCT

patch by slebresne; reviewed by thobbs for CASSANDRA-6857
Allow deleting snapshots from dropped keyspaces
patch by Lyuben Todorov; reviewed by Nick Bailey for CASSANDRA-6281
Make cqlsh prompt for a password if the user doesn't enter one.

patch by J.B. Langston; reviewed by Mikhail Stepura for CASSANDRA-6902