Added stdio. Output to the console can be done with printf now.
Thing freezes/breaks when printf() requires scrolling. Does not seem to
happen with delay_ms (like in the demo code). delay_ms does not
work with I2C well. Race condition, I'd reckon.

demotext and teletext styles in extra files.
code cleanup
- GNU Style code indentation from now on
- Defining DEBUG enables onscreen messages.
- single header for C and ASM now.
- some fixes