Code changes according to Spark, Shark and Tachyon upgrade
Modify spark-stack version to 0.9 and exclude asm to eliminate runtime exception
ShortWritable is introduced by cdh but not compatible with standard apache hadoop
Use second value of tuple in KafkaDstream, since kafka is upgraded to 0.8-beta-1
Make shark-service configurable by environment var DISABLE_SHARK_SERVICE
Change the comment line prefix with --
Enable tachyonRDDOutput format for weblog W/O the shark service
Modify the TBLPROPERTIES ("shark.cache" = "true")