Added convenience method to remove all children from an ActorContainer
CAAT Path incorrectly assumed the starting point is always the first point of the first path segment. EG: when creating a path consisting of arcTo path segments, the first point is NOT the first arcTo path segment point.
Path.beginPath should register the specified starting point (like documented...) and use that as a starting point, with a fallback to the first path segment point when the starting point was not specified.