Copied from gist git://gist.github.com/1216527.git
Added extra events for when a slide loses current/prev/next status

As per Gist git://gist.github.com/1228641.git
Implements event direction.

Events can have one of two directions passed to them -- forward or reverse.
This depends on whether or not the "new" slide number is higher or lower
than the old one. Using these, reversible events can be implemented
(see #1).
Added README
Added README
Merge branch 'master' of github.com:nemec/deck.events.js
Merge branch 'master' of github.com:nemec/deck.events.js
Merge branch 'master' of github.com:nemec/deck.events.js
Merge pull request #2 from nemec/master

Implements event direction.
moved "events" extensions to a subfolder to match the other ones
[step] added a simple step extension that enables stepping without considering sub-slides.
[animate] added the animate extension with some simple but cool functionalities
[animate] and() undoes and inits in reverse order
[animate] fixed name
[animate] play/pause animations for video tags
[smartsyntax] added smartsyntax extension which is based on the custom format from my xhtml-presentation framework
[simplemath] use latex notation to write maths
[simplemath] cleaned js file (removed unneeded things coming from smartsyntax)
[smartsyntax] now handles the $f(x)$ convention for maths (generates a span to be interpreted by the simplemath extension)
[simplemath] run math on deck.init so as to have good interaction with the rest (smartsyntax)