check if the viewport size actually changed on resize. fixes #271
0.6.10
fixed path example on mobile
Implemented event optional event emitter.

The event emitter emits events when the before, between and after classes are set,
and allows developers to more freely bind actions to the different events.
Added simple docs for the event emitter
Added missing IE check before instantiating Events
Updated the skrollr.min.js file
Removed the calls to _emitEvent from around the code and replaced it with one call from inside the _updateClass function instead
Updated the skrollr.min.js
adding /kbrabrand/skrollr/ for declaring events