add documentation to crate spawner / dropper
purge the classic mods from the source tree

they are unmaintained and no one wants to play them
Move gdi01 and nod01 back to cnc
Merge pull request #3120 from Mailaender/classic-removal

Goodbye classic mods
Start moving towards saner RA widget logic. This switches players to observer mode after they have finished playing in RA/D2k and removes some legacy code.
Fix RA cheats widget not closing when the cheats button is clicked