new hadoop_jvm module for java/scala hadoop jobs.

* new JvmJobTask and extracted some common functionality from
  HadoopJobTask into BaseHadoopJobTask
* moved jobconf logic into the BaseHadoopJobTask
* bare-bones JvmHadoopJobRunner and extracted common functionality
  from HadoopJobRunner into static methods (submitting/tracking a
  job).
Updates from review.

* renames hadoop_jvm -> hadoop_jar, and JvmHadoop* to HadoopJar*.
* remove NamedHdfsTarget
* New example for terasort/teragen.
more review feedback.

* atomic file renames.
* more docs.
* cleaned up example args.
Merge pull request #9 from jcrobak/java-support

new hadoop_jvm module for java/scala hadoop jobs.