Easy math for bulb@

Since bulb@ had some trouble understanding my comments on Ye Olde Plasma and seems to be new to the Atari scene (and actually also to the rest of the scene if not even the whole world) I decided to follow his suggestion and add a little guide here. The Atari Composite file format is a segments file format originating from Atari DOS 2.5. Each segment consists of the start address and the (inclusive end address). The first segment requires $ffff as additional prefix, adding a total of 6 bytes to the file length a minimum file. Though this header is larger than the 2 byte C64 header it is still much smaller than the header of for example Atari ST executable format. Therefore compo rules of Atari related parties like Forever take the header into account and refer to the file size, like this is done on most other platforms. This means that this actually quite nice intro does not fit in to the 256 bytes category on Atari 8-bit. So bulb@ selected the wrong category, but hey that happens. And instead of starting to bash him, I contacted the coder Dimitry instead, sent some respect for cross platform coding and gave some tips on how to even make this better and smaller. I like the scene, competition and exchanging ideas with cool people. I actually don't like trolls, though.