Added `root` option and made `bindEventHandlers` public

The `root` option determines where the `click`, `mouseover` and `touchstart` events should be bound to. This allows links outside of the $container to load using SmoothState.js.

`bindEventHandlers` has been made public to allow the user to manually rebind all events. For example: if `$("*").off()` has been called, and all event handlers have been destroyed, then it is necessary to re bind SmoothState's events.