Font upload

[thejpster]

Could support soft loading fonts. One function takes a 4096 (8x16) array, the other a 2048 (8x8) array.

Also need to document that default font must be Code Page 850. Or we should return the code page of the default font.

[CHiPs44]

Or perhaps a function with 2 parameters: size and code page?

[thejpster]

The BIOS doesn't do much with the font after the OS has started. It shows the HardFault error but we can switch back to the default font for that. So I don't think the BIOS needs to know the code page of any given soft font. Or even that it matches a known code page.