Added ability to print bitmap

I have added the ability to print monochrome bitmaps using the printBMP(char[2048]) function, which allows for bitmaps of size 128 by 128 to be displayed on the screen. I know this is now a defunct library as you no longer publish the product, but it may be of use to someone. I had originally intended to improve it so that you could display bitmaps of any size in full colour, but I haven't gotten round to it, and I can't see myself completing it anytime soon. I've added in an example, that describes how to use the new feature.