2019/11/19
- added PDV paraview file reading.
- PDB protein data bank file reader
- added error bars in plotxy()
- fast fitting of 2d circles with utils.fitCircle2D()
- added flag-style pop-up labels for meshes and volumes
- added settings for resolving polygonal clashes with mesh edges
- built in set of parametric surfaces in shapes.py module
- improved plotting2d with error bars
- added warpMeshToPoint() method
- improved texture control, can pass texture coords explicitly
- fix trimesh problem with coloring vertices
- can use "panel" backend in notebooks



