Some improvements to DistributedCacheJars, KijiTransformJobBuilder, HFileReducerMapReduceJobOutput.

 - Changes DistributedCacheJars audience to public.
 - Better JavaDoc for KijiTransformJobBuilder.
 - Adds audience annotation of framework to HFileReducerMapReduceJobOutput and moves it.
Renames KijiTransformJobBuilder KijiMapReduceJobBuilder.

- KijiTransform tool becomes KijiGeneralMapReduce. Command is 'kiji mapreduce'.
- Javadoc of class and description of tool improved for clarity.
- Tests updated.