Datagristle

* gristle_differ
- totally rewritten. Can now handle very large files, perform post-transform
transformations, handle more complex comparisons, and use column names rather
than just positions.
* gristle_determinator
- added read-limit argument. This allows the tool to be easily run against a
subset of a very large input file.
* gristle_scalar
- removed from toolkit. There are better tools in other solutions can be used
instead. This tool may come back again later, but only if enormously rewritten.
* gristle_filter
- removed from toolkit. There are better tools in other solutions can be used
instead. This tool may come back again later, but only if enormously rewritten.
* minor:
- gristle_md_reporter - slight formatting change: text descriptions of fields are
now included, and column widths were tweaked.
- all utilities - a substantial performance improvement for large files when
quoting information is not provided.

* gristle_dir_merger
- initial addition to toolkit. Merges directories of files using a variety
of matching criteria and matching actions.

* gristle_processor
- initial addition to toolkit. Provides ability to scan through directory
structure recursively, and delete files that match config criteria.

* gristle_determinator
- added hasnoheader arg
- fixed problem printing top_values on empty file with header
* gristle_validator
- added hasnoheader arg
* gristle_freaker
- added hasnoheader arg

* gristle_determinator - fixed a few problems:
- the 'Top Values not shown - all unique' message being truncated
- floats not handled correctly for stddev & variance
- quoted ints & floats not handled

* gristle_validator - major updates to allow validation of csv files based on
the json schema standard, with help from the Validictory module.