Implement dual-mode programs

[jezze]

With dual mode I mean programs that can operate both in a CLI and in a GUI context. Right now I have a shell and a wshell program that works in CLI and GUI respectively. It would be nice if I could use the same program for both. Another example is the mandelbrot program. I wish it could detect that if it is in a GUI it will not try to set video mode but instead just render in the video mode it currently uses. Before rendering it will try to grab the video from the wm.