Make disruptor_thrift_server invocation pool configurable
patch by Pavel Yaskevich; reviewed by Jason Brown for CASSANDRA-7594
Merge branch 'cassandra-2.0' into cassandra-2.1

Conflicts:
	CHANGES.txt
	build.xml
	lib/thrift-server-0.3.5.jar
	lib/thrift-server-0.3.6.jar