Deal with conflicts between system functions and UDFs

patch by Robert Stupp; reviewed by Benjamin Lerer for CASSANDRA-7813
Allow snapshot-based repair on Windows for 3.0

Patch by jmckenzie; reviewed by yukim for CASSANDRA-8309
Remove post-2.1 dead schema migrations and columns
Fix CFMetaData compaction-related warnings
Merge branch 'cassandra-2.1' into trunk
fix test throw unknown keyspace error
don't declare throwing exceptions that aren't
remove dead field
avoid npe chance, use == with enums
Ninja: fix test for js return type under rhino engine
Temporary fix for CASSANDRA-8326

This is a temporary python driver fix for CASSANDRA-8326.  The patch
has not been properly reviewed and tested by the python driver team.
The driver version bundled here can be found at the following branch:

https://github.com/thobbs/python-driver/tree/CASSANDRA-8326-temp-fix
Fix IRE with ORDER BY, treating all selections as fns

Patch by Tyler Hobbs; reviewed by Benjamin Lerer for CASSANDRA-8286
Merge branch 'cassandra-2.0' into cassandra-2.1
Merge branch 'cassandra-2.1' into trunk
Fix multicolumn relation + COMPACT STORAGE issues

Patch by Tyler Hobbs; reviewed by Benjamin Lerer for CASSANDRA-8264
Merge branch 'cassandra-2.0' into cassandra-2.1
Merge branch 'cassandra-2.1' into trunk
Fix CONTAINS (KEY) filtering on frozen collection clustering cols

Patch by Tyler Hobbs; reviewed by Benjamin Lerer for CASSANDRA-8302
Merge branch 'cassandra-2.1' into trunk
Centralize shared executors

patch by Sam Tunnicliffe; reviewed by Aleksey Yeschenko for
CASSANDRA-8055