The autogenerated icons are in most cases ugly, do not conform to the
style of the other icons, and do not respect relative dimensions and
positions. The math icons have a vertical dimension of 19 pixel, defining
a grid that has to be respected for obtaining correct alignment.
The only autogenerated icons that remain are those of the Misc (extra)
toolbar. I plan to also replace them in the near future.
These are all generated by development/tools/generate_symbols_images.py, the
only manual adjustments were renamings due to case sensitive file systems on
windows.
