Refactor log upload to create JSON via obs_data
Remove unused variable
Use fontconfig for linux/mac

This uses fontconfig for looking up font files for freetype to use on
both linux and mac.  It's apparently a bit more optimal and prevents us
from having to worry about the load time on the mac version as well.

Refactored and moved all the old code to the find-font-windows.c file,
as it's no longer used on anything but windows.