First commit of python script to process query.json files.

This script generates many histogram.json files containing info
needed to generated the pixel coverage charts for every possible
combination of layers in a Cinema data set.
Added first pass at storing image paths into bins for searching.
Add linear index id to refer to image files, remove empty image lists.
Merge pull request #26 from Kitware/add-query-json-processing-script

WIP: Add query json processing script