Remove unused FindResArg
Make arg processing static
Simplify AppendIniArgs
Move common/3d/draw.c -> common/3d/draw.cpp
Move common/3d/globvars.c -> common/3d/globvars.cpp
Move common/3d/instance.c -> common/3d/instance.cpp
Move common/3d/matrix.c -> common/3d/matrix.cpp
Move common/3d/points.c -> common/3d/points.cpp
Move common/3d/rod.c -> common/3d/rod.cpp
Move common/3d/setup.c -> common/3d/setup.cpp
Move common/arch/sdl/joy.c -> common/arch/sdl/joy.cpp
Move common/arch/sdl/rbaudio.c -> common/arch/sdl/rbaudio.cpp
Move common/arch/sdl/window.c -> common/arch/sdl/window.cpp
Move common/maths/fixc.c -> common/maths/fixc.cpp
Move common/maths/rand.c -> common/maths/rand.cpp
Move common/maths/tables.c -> common/maths/tables.cpp
Move common/maths/vecmat.c -> common/maths/vecmat.cpp
Move common/misc/error.c -> common/misc/error.cpp