Add PigUnit unit tests.
Patch by Alex Liu, reviewed by brandonwilliams for CASSANDRA-5695
Merge branch 'cassandra-1.2' into cassandra-2.0

Conflicts:
	build.xml
	src/java/org/apache/cassandra/hadoop/pig/AbstractCassandraStorage.java
Skip replaying mutations that pass CRC but fail to deserialize
patch by jbellis; reviewed by Lyuben Todorov for CASSANDRA-6183
merge from 1.2
Increase CQL2 and CQL3 internals' visibility

Increase CQL2 and CQL3 internals' visibility for external introspection