Glk extension proposal: Pixel Ratio

It’s hard to see how the behaviour would change in a way that would be unambiguously better. Fonts are specified in terms of point size, which is why going to a 150% display makes the font bigger. But if a graphic is drawn in a text buffer at full size, scaling that up by 150% looks just horrible. This sort of thing is why all these high DPI issues are hard to solve.