Added Glossary

@jboner Glossary has been built out. Please ignore the branch name - I called it appendix by mistake!  

The main title 'The Reactive Manifesto' on the glossary page links back to the homepage. I've also made the footer link back as well. Each term in the glossary has an HTML ID associated with it, so that it's easy to build links such as /glossary#Location-Transparency that anchor down to the actual term. 

![glossary](https://cloud.githubusercontent.com/assets/1418129/4638273/22ddb3f6-53f8-11e4-8b3f-385cb2c5bc68.png)