home and end key use

Adding example for custom event bindings.

hjkl for directions.
space to move to next slide.
esc for 3D overview (instead of space)

Overview mode shows hidden fragments. (closes #30)

change back state event scope, document level makes more sense as that's where the state class is applied

Firing custom event based on data-state name. This allows developers to trigger custom javascript code on a per slide basis.