highlight, link, strikeout, squiggly and underline annotation types may define a set of quadrilaterals using the quadpoints entry. this defines the regions to show/activate the annotation. the order of points in the quadpoints array does not match the specification so we provide a convenience class to access the point data rather than interpreting it as a rectangle: https://stackoverflow.com/questions/9855814/pdf-spec-vs-acrobat-creation-quadpoints.
