grafx - Extensible Java Graphics Package Code

Fixing the issue with thread lock. I noticed that mouseDrag() and update() are
always called from the same thread.

Adding beginnings of 'Donut' for demo purposes.

Making use of MatrixUtils in PolyhedronDemo. This demo is still freezing
occasionally:
Exception in thread "main" java.lang.RuntimeException: trying to update() in vain
at com.nerius.game.util.CanvasAWTAdapter.requestUpdate(CanvasAWTAdapter.java:187)
at com.nerius.grafx.d3.demo.PolyhedronDemo.run(PolyhedronDemo.java:253)
at com.nerius.grafx.d3.demo.PolyhedronDemo.main(PolyhedronDemo.java:72)

Adding helper class 'MatrixUtils' to package 'com.nerius.grafx.d3.demo'. At
lease two classes in same package (demo code) will likely be making use of
this.

Removing a TODO.txt item that has already been completed.

Fixing GrafxPolyFillDemo to work without java.applet.Applet.

Updating PolyhedronDemo to do away with usage of java.applet.Applet. I think
this works, even though there was one small hiccup recently; there may be some
thread safety issues still lurking somewhere.

Changing order of member variable definitions, used to be m_anim, m_grafx, and
m_img; it's now m_grafx, m_anim, and m_img.

Correcting some spelling mistakes in CanvasAWTAdapter, which are in comments.
'insure' -> 'ensure'.

Fixing GrafxLineDrawDemo to be standalone.