Adding glyphs to Arabic fonts

Hi Dave et al
I've added a page on the above as you suggested, and also included an (optional) appendix on installing FF on Ubuntu 14.04.  I also added a note to README to say you need ruby-dev installed before gem install jekyll will work. 
Kevin
> But I didn't want to start making changes to someone else's stuff.

Well&hellip; that's kinda the point of collaborative work. Go ahead, it's fine.

> It won't show up on the webpage, will it?

Yeah I think HTML ignores it.

> Pretty standard in LaTeX.

But LaTeX replaces them at compile-time.

> I did try using &ndash;, but Jekyll refused to generate the pages then.

Really? It's already used in other parts of the tutorial. What error message do you get? 
Please do the change whatsoever, it's already in place elsewhere.

> Hmm. In my experience that assumption is usually unjustified. Can you reword yourself to whatever you're happy with?

Can you word it like: "Some licenses allow modifications of the fonts to the user, notably the SIL OFL or the GNU+Font Exception". So that we don't have to have that "You're not allowed to modify commercial fonts" paragraph.