Comments update
Cleaning up things for a the DemoLines
Tentatively replacing a simple demo to use anti-aliasing, for testing
Minor thing
Comments for rectangle positions locations were incorrect in the Javadoc
`DemoMixer` update, not finished yet.
Some problems with the drawing of the rectangles have to be fixed first,
notably because they don't rotate correctly (`GdxGraphics` issue).
Merge branch 'master' of https://github.com/pmudry/gdx2d.git

Conflicts:
	gdx2d-desktop/src/hevs/gdx2d/demos/physics/joints/DemoMixer.java