Support multi-row selects within a partition using IN

Patch by Tyler Hobbs; review by Sylvain Lebresne for CASSANDRA-6875
Merge branch 'cassandra-2.0' into cassandra-2.1

Conflicts:
	CHANGES.txt
	src/java/org/apache/cassandra/cql3/Cql.g
	src/java/org/apache/cassandra/cql3/Lists.java
	src/java/org/apache/cassandra/cql3/QueryProcessor.java
	src/java/org/apache/cassandra/cql3/Relation.java
	src/java/org/apache/cassandra/cql3/ResultSet.java
	src/java/org/apache/cassandra/cql3/statements/BatchStatement.java
	src/java/org/apache/cassandra/cql3/statements/ModificationStatement.java
	src/java/org/apache/cassandra/cql3/statements/Restriction.java
	src/java/org/apache/cassandra/cql3/statements/SelectStatement.java
Merge branch 'cassandra-2.1' into trunk