2.5.0

- URL hash now updates immediate, was previously delayed to account for a legacy Chrome bug
- Rolling links are now turned off by default, will be removed entirely in the long term
- Leap Motion plugin 
- MathJax plugin
- Support for notes in external Markdown
- Fix bug with ```auto-slide``` on first slide (#525)
- Fragments on upcoming slides are no longer visible when navigating back and forth in the presentation
- Added an ```none``` transition setting for slide backgrounds
- O key can now be used to toggle the overview mode, useful since ESC does not work in fullscreen mode
- Greatly simplified client-side notes plugin, fixes issues where fragments went out of sync
- The framework will no longer query the DOM before ```Reveal.initialize``` is called. This allows reveal.js to be loaded in the ```<head>```
- Fixed bug that caused slideshow to break if an invalid named link was referenced
- Added ```.stretch``` helper class for dynamically expanding an element to fill its parent slide
- Fixed issues where past/future slides were clickable even if they weren't visible
- Optimization:
  - Much more accurate way of hiding slides that are out of view
  - Configurable ```viewDistance``` (# of slides from current that should be hidden)
  - Short view distance for mobile devices