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
Please don't put 2 spaces after sentences, [it's a typewriter habit](http://www.slate.com/articles/technology/technology/2011/01/space_invaders.html).