Remove natsort, a temporary dependency used in transys.py
Remove natsort, a temporary dependency used in transys.py

This commit rolls back 9bf4fb42583ac9e7c77449e62cae2f12f1858e92
and afc5d2144ab817f917ecc85182a992eb30c75140
which had introduced natsort (https://pypi.python.org/pypi/natsort
; https://github.com/SethMMorton/natsort) for the purpose of easily
sorting lists "naturally". It was a temporary dependency motivated
by debugging the jtlv interface.

tulip-control/tulip-control,necozay/tulip-control,tulip-control/tulip-control,tulip-control/tulip-control,necozay/tulip-control,tulip-control/tulip-control,necozay/tulip-control,necozay/tulip-control,necozay/tulip-control