Clean and parallelize

Tim,

This is my version of your time-harvester.  Feel free to include any of it in yours.... Changes:
1. it is more unixy in that all it does is output json to standard out or throw an error. I did this so I could pipe the output directly into something else.
2. I removed the task code mappings, Jeremy's script does this already.
3. Parallelized the calls to Harvest, so it is faster.

Michael