Loading XML module, registering etree namespaces... etc
on startup for everyone on chance someone may want to export
an SVG from Freestyle is unacceptable.
This shouldn't have got through the review.
also disable loading when built without freestyle.
Features:
* Both still image and animation rendering, as well as polygon
fills are supported.
* The exporter creates a new SVG layer for every Freestyle line
set. The different layers are correctly sorted.
* SVG paths use data from line styles, so the base color of a
line style becomes the color of paths, idem for dashes and
stroke thickness.
* Strokes can be split at invisible parts. This functionality is
useful when exporting for instance dashed lines or line styles
with a Blue Print shader
* The exporter can be used not only in the Parameter Editor mode,
but also from within style modules written for the Python
Scripting mode.
Acknowledgements:
The author would like to thank Francesco Fantoni and Jarno
Leppänen for their [[ https://github.com/hvfrancesco/freestylesvg | Freestyle SVG exporter ]].
Differential revision: https://developer.blender.org/D785
Author: flokkievids (Folkert de Vries)
Reviewed by: kjym3 (Tamito Kajiyama)
