Added Point.setTo
Added Rectangle.toString
Altered Point and Rectangle toString()

Vector3D.toString shows the type as part of its formatting. I altered
Point and Rectangle to do the same, for clarity.
Added Rectangle.copyFrom
Added Matrix.setTo
Added Matrix.toString
Added Matrix.copyFrom
Added several Matrix copy methods

copyColumnFrom, copyColumnTo, copyRowFrom, copyRowTo.
Someone should probably verify my implementations; Never used these
methods before.
Removed inline declarations from Matrix3D methods
Added several Matrix3D copy methods

copyFrom, copyToMatrix3D, copyColumnFrom, copyColumnTo, copyRowFrom,
copyRowTo
Fixes to Matrix3D

Added pointAt implementation found in openfl-html5; Someone should
verify that implementation, don't know why it was commented out but it
was the only one I had at hand.

Fixed copyFrom/To issue with vector.concat(). Apparently concat() don't
fly the way it does in AS3?