Line collision detection by Tom

Feel free to pinch any code you like from the sources to use with your own programs, just
give me a mention in any accompanying documentation or any scrolltexts ;)

Instructions

This is a /very/ simple piece of code that I knocked up in half a hour to test the
functionality of the routine in line.c. If you hold the button with the same colour as
a line endpoint, you can move it around with the d-pad. If the lines cross, the number
displayed on the screen will be 1, otherwise it'll be 0. Press start & select together
to quit. Simple, but effective.