Today I've added the support for adding ttf fonts to ImGuiGML.

Use: 

imguigml_add_font_from_ttf(_filename, _font_size) to add your font, where the filename is a valid path to a ttf file, and the size is the font size in pixels.

This function will return an index you can use with imguigml_push_font(_font_index), as well as check its validity with imguigml_is_font_valid(_font_index).

Let me know if you have any issues!