Move 2d/2dsline.c -> 2d/2dsline.cpp
Move */main/weapon.c -> similar/main/weapon.c
Move */main/aistruct.h -> common/main/aistruct.h
Defer PlatformSettings env back to program env
Move argumentIndirection(prefix) up to DXXProgram
Show prefix list for each program target
Show instance numbers on DXXProgram runs