all PNG handling

fix an annoying bug with PNG and 4 bit palette...

GroSSe Windows Bug!

Last release cannot run with windows because of stack size...

changelog:

• bugfix last color of hardware sprite palette (wasn't displayed)
• new tiles option (general tilemap, tiled screen, metatiles, tileSheet preview)
• fix transparency for tiles + width count
• rotoffset map generation (very specific export for demo FX)

x64 release if you are brave enough

build MacOS thanks to Sid/iMPact!