This changes the text hinting setting to be an enum with options
Auto / None / Slight / Full. The default is Auto which currently disables
hinting.
The hinting was tested with a new FreeType version, but this is not what
is used on the buildbots an official release environment, and the fonts
look quite bad because of that. Once FreeType has been upgraded we can
change the default.
Even then the results are not ideal, perhaps due to missing subpixel
positioning and linear color blending support in BLF.
34029fc71a