HBASE-9165 [mapreduce] Modularize building dependency jars

 - Separate adding HBase and dependencies from adding other job
   dependencies, and expose it as a separate method that other
   projects can use (for PIG-3285).
 - Explicitly add hbase-server to the list of dependencies we ship
   with the job, for users who extend the classes we provide (see
   HBASE-9112).
 - Add integration test for addDependencyJars.
 - Code reuse for TestTableMapReduce.


git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1542341 13f79535-47bb-0310-9956-ffa450edef68