ParabolicPath rendering for Launch Stars and Sling Stars

[chendeni]

I have a request for a new feature. If a Launch Star has a path with exactly 2 points, the game will calculate a parabolic path instead of a Bezier spline. Currently, Whitehole does not render the path, so creating a parabolic Launch Star path or placing objects along the path requires a lot of guess and check. Adding a ParabolicPath renderer for Launch Stars, Sling Stars, and Star Ball launchers would make editing them a lot less tedious.