added roles/scala subtree info to .gittrees
moved spark vars to spark_standalone roles
moved ampcamp vars to ampcamp role
moved mesos vars to mesos role
moved shark vars to shark role
move tachyon vars to its role
moved hive vars to its role
moved mysql vars to its role
moved hadoop vars to hadoop_common role
moved nfs vars to nfs_ roles
extracted mpi cluster related things to separate playbook
fix typo in  hadoop vars
bugfixes