Just fixed a big blocker for FLTK >= 1.4.

Blurry fonts were caused by a half pixel misalignment bug in FLTK which broke the font hinting leading to poor readability. Should be fixed in next FLTK 1.4.5 release.

I was not expecting to having to follow this whole font rendering pipeline rabbit hole. I'm surprised how little information there is on the Web about this topic, maybe I write more details later.