Replace binary OTF file with text-based SFD format

This should definitely be checked by someone who knows more about these things, but if the SFD format preserves all the necessary information, having a text based format will make it much easier to collaborate on updating the font.

It looks like SFD is not standardised, but the application that edits it (Fontforge, http://en.wikipedia.org/wiki/FontForge) is open source (BSD licensed) and cross platform. I made this file simply by loading the OTF file in Fontforge and saving it, with no changes.