add scratch HTML and JS for rapid development (without compilation).
add svg.provider.Point and svg.event.EventType to prepare for binding.
turn svg.Bezier into a base class to provide event target to subclasses.
svg.Bezier3: remove needless overriding method.
svg.Bezier3: add experimental method accepting a bound SVGPoint.
reduce noise in the path and pathData APIs (breaking demo temporarily).
svg.Path: listen for changes to component svg.Bezier3 instances.
demo: update path demo to use experimental event binding.
demo: unbreak the path demo by removing a goog.exportSymbol and comment why.