Move similar/arch/sdl/gr.c -> similar/arch/sdl/gr.cpp
Move similar/arch/sdl/digi_mixer.c -> similar/arch/sdl/digi_mixer.cpp
Move similar/arch/sdl/jukebox.c -> similar/arch/sdl/jukebox.cpp
Move similar/2d/font.c -> similar/2d/font.cpp
Move similar/2d/palette.c -> similar/2d/palette.cpp
Move similar/2d/pcx.c -> similar/2d/pcx.cpp
Move similar/3d/interp.c -> similar/3d/interp.cpp
Move similar/arch/sdl/digi.c -> similar/arch/sdl/digi.cpp
Move similar/arch/sdl/digi_audio.c -> similar/arch/sdl/digi_audio.cpp
Move similar/arch/sdl/event.c -> similar/arch/sdl/event.cpp
Move similar/arch/sdl/init.c -> similar/arch/sdl/init.cpp
Move similar/arch/sdl/key.c -> similar/arch/sdl/key.cpp
Move similar/arch/sdl/mouse.c -> similar/arch/sdl/mouse.cpp
Move similar/arch/sdl/timer.c -> similar/arch/sdl/timer.cpp