Expose rendered text width and height in Sup.TextRenderer

[elisee]

We have those internally, we should make them available in the API.

[notexplosive]

Something else I'd like to see is if we could ask a Font asset how wide a particular character is. Something like this.actor.textRenderer.getFont().getTextWidth('a') so that way I can calculate my spacing without having to render it. This might be worth opening a different issue for.

Edit: Apparently this is already a thing. Well now I feel silly.