Auto-resizing font renderer using Pango

[Gjum]

The new leaderboard using right-aligned text without a background is claimed to be hard to read. I want to include an option to bring back the default leaderboard style.

For this, rendering long text in a smaller font would be cool, so that it still fits into the fixed-size box. This can then also be applied to cell nicks.

Some symbols cannot be rendered with the default font. Also, cairo_show_text is only intended for demo purposes, so all font rendering should happen with Pango instead.