Adds a FontImporter

This importer adds a simple way to load fonts like you can import sprites

In your .scss file, just add the following line to import all fonts in your font directory
   @import "fonts:*";

You can also import your fonts more selectively by changing the glob:
   @import "fonts:Museo/*";

This will read the name of the font from the TTF file, and make it available as a variable.
It will also load the font. The variable name gets downcase.

So if you have a font named MuseoSlab-500, the variable will be named $museoslab-500

WARNING: This works by reading TTF files from your fonts folder.
If you're not working with TTF, this won't work for you