Did a first step towards runtime configuration. I removed all those
hardcoded options (the #ifdef's) and replaced them with normal if's. The
whole configuration for vgetty is now in config.h. I probably broke lots of
stuff, also vgetty still works on my machine. For now You have to edit
config.h, but in future releases config.h will only be the default values
and configuration will be done with a configuration file. So far for now...

Marc
