This patch removes several stroke shaders written in C++ that are unused
and don't serve a real purpose any more. The removed shaders are:
- BPy_ColorVariationPatternShader
- BPy_StrokeTextureShader
- BPy_TextureAssignerShader
- BPy_ThicknessVariationPatternShader
- BPy_fstreamShader
- BPy_streamShader
and a few more that weren't even exposed to the Python API.
Some minor edits were made by the reviewer.
Differential Revision: https://developer.blender.org/D801
Reviewed by: kjym3