Move NetKAN files to their own folder.
Added Netkan tools

Identical to 380c5cb4b2bc0be05068846e2570f62026ef436c
Renamed all fragmets to .netkan extensions

This makes it easy to see what's an input file, and what's an output
file. We're also gitignoring `*.ckan` files, so we don't commit output
files by accident.