#20 Upgraded CDH from 5.1.0 to 5.2.1

Upgraded CDH from 5.1.0 to 5.2.1, HBase from 0.98.1 to 0.98.6 and updated maven compiler (target) version to 1.7. Removed dependencies hbase-common, hbase-client and hbase-protocol as they are transitive dependencies of hbase-server already (also to keep the version consistent with server). Removed dependency hadoop-core and hadoop-common and added hadoop-client instead. Added dependency for jsch.  Removed comments and commented out lines.