Bespoke overview

Added an overview mode for Bespoke to allow the user to choose a transition style.
Dropped Reveal.js support (GH-175) as Bespoke can do nearly everything Reveal.js can do and Bespoke does it better and more simply.

A humorous example of the flexibility of Bespoke: http://markdalgleish.com/presentations/bespoke.js/

Reveal was also a continual headache and just one more thing to maintain whenever adding new features.  Various bugs in the reveal.js data-state api, excessive configuration requirements, reveal is a large amount of code for what should be pretty trivial.

Things missing from bespoke that would be nice to have:
escape -> overview
"basement level" slides