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
Plase replace `--` with `&ndash;` (the [endash](http://en.wikipedia.org/wiki/Dash#En_dash)), the hyphens in a row is a typewriter habit.