Hive fixes

A bunch of fixes to improve hive.

* Wrap ouput source for HiveJobs in options. For none it will then use a NullTap.
* Disabled staleness check for hive queries.
* Fixes to the hive partition sources so that cascading can do proper scheduling based on sources and sinks.
* Documented partitioning limitation.
* Split the tools into a separate sub project so that core no longer needs the assembly step and this also fixed an issue with regards to hive and packaging. This closes #35.
* Upgraded versions of cascading-hive via cascading-beehaus. This closes #37.
Updated comments.