Improve support for fonts

Many fonts that work in other software don't work in Blender.

Here is a quick test with the five most popular fonts (.ttf files) from Google Fonts, where three out of five are broken in Blender. These fonts work fine in other apps and software I tested them with, but not Blender.

A close-up of the Roboto font in Edit Mode where the letters are unreadable due to overlapping faces.