Blender Git Loki

D319: Freestyle Python scripts update.

This revision is meant to update Freestyle's Python scripts to make full usage
of the new features of Python and Freestyle's Python API.

Freestyle's Python scripts are pretty old already, and were never given much
attention. With the 2.7x generation of Blender coming up, this is an excellent
time to update Freestyle's Python scripts, hopefully adding some new features
and achieving some speed improvements on the way.

Main goals:
* use for loops where possible
* general cleanup, making use of more recent python features (generators,
ternary operator, ect.)
* update the documentation on the way (it's lacking atm)


Differential revision: https://developer.blender.org/D319

Author: flokkievids (Folkert de Vries)

Reviewed by: kjym3 (Tamito Kajiyama)