Require Permission.SELECT for CAS updates

patch by Aleksey Yeschenko; reviewed by Sylvain Lebresne for
CASSANDRA-6247
Merge branch 'cassandra-2.0' into trunk
Require logging in for Thrift CQL2/3 statement preparation

patch by Aleksey Yeschenko; reviewed by Sylvain Lebresne for
CASSANDRA-6254
Merge branch 'cassandra-1.2' into cassandra-2.0

Conflicts:
	CHANGES.txt
	src/java/org/apache/cassandra/thrift/CassandraServer.java
Merge branch 'cassandra-2.0' into trunk