Font support

What type of fonts does it support?
I tried to pick some fonts from https://www.dafont.com and none of them are printed correctly(no colour in pdf).

Example font: https://www.dafont.com/gobold.font

What I did was just running test at 
https://github.com/jbowtie/gutenex/blob/opentype/test/font_test.exs#L26
with the new fonts downloaded.