bumped version of cassandra and pycassa that we use to be the newest versions
installing new version of cassandra, to fix possible silent write failure
bumped Xss to 160k because Java 7 requires it to run Cassandra
reverted log level back to INFO
Merge pull request #568 from shatterednirvana/cassandra-1.2.5

Update Cassandra to version 1.2.5