Adding precision hit test to NGon

Enabling precision hit tests for NGons in two ways: For simpleNGons
(circles, elipses) with more than 20 sides, assume circle or ellipse is
desired, test point against radius.
For Fans, Hoops and Arcs, verify against triangles in geometry. Slower,
ofcourse.

Also, fixing crash after new uvMatrix-rewrite. In a regular NGon, the
uvMatrix is null, have to be tested against.
See:

https://github.com/StarlingGraphics/Starling-Extension-Graphics/issues/83