This update brings some significant changes to the Cascadia family:
* Arabic and Hebrew support
* Italics (the new ones, not the cursive ones)
* Tweaked letterforms and fixed interpolation values for the upright
faces.
Since we now have four font files, this commit also relocates them to a
much more reasonable place (res/fonts/) and tidies up the build and
exclude rules to make them more extensible in the future.
