Update README with INCBIN and image converter details

Added information about INCBIN and Spetra image converter.

Author: mtg101

README.md

@@ -7,3 +7,6 @@ My 'game' is just a sprite that moves and can affect lives / score / energy. But
 Border resolution is only 11 columns, using OUTI to read directly from memory, rather than the maximum resolution of nearly 15 columns using self-modifying code as I did in my border demo: https://github.com/mtg101/Open-Borders -- this just makes things easier for someone to actually write a game around the scoreboarder engine. 
 
 And to make things more complicated... I've added a horizon effect with clouds. My demo 'game' can afford to lose 32 rows of t-states for it. Others can use it if they can afford it, or just stick to the main scorboarder. 
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+One learning from this project is INCBIN. Allows including a binary file, which when ORG'd to screen memory shows as the screen. And I discovered Spetra image converter for creating those binary images: http://www.fruitcake.plus.com/Sinclair/Spectrum/Spectra/SpectraInterface_Software_ImageConverter.htm 
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