Add points: u32 parameter to graphics::Font::default_font func

[ozkriff]

Or create another function like graphics::Font::default_font_with_points(points: u32) -> GameResult<Self>.

[Ratysz]

Ideally, we'd allow the user app to override default font (via config or builder) entirely during context creation. This is very relevant to #362, and I have a few ideas how to handle it better - but the changes have to be sanity-checked and merged first.

[icefoxen]

I like Ratysz's idea. But now that I think of it, default_font_with_points() or such would be pretty easy to make... But then we'd need default_fonts_with_px() as well. Might be nice to separate "a font with size information" from "raw font data" somehow...

Really the only reason I included a default font at all is to make life easy for writing debug text.

[icefoxen]

This is now obsolete since gfx_glyph takes size information when text is drawn, not when the font is loaded.