Version 0.88:

- migration from SDL2 to SDL3
- pattern option for stamp brush (large brushes can still be problematic)
- free rotate tool (not yet working properly)
- native file dialog using SDL3, strange event issues possibly fixed now, also no longer needs windows.h
- big speed optimization in color shelf drawing, in some systems the old routine would halt the program
- tile texture is now using a streaming texture
- 8 bugs fixed
- double buffer drawing fixes, the backbuffer can still be trash in some situations, but it's only a visual bug