Button should still fire the change listener when disabled and checked state is changed programmatically.
It appears sorting based on y up/down is not necessary.

It gives incorrect results with clockwise, colinear points.
Merge branch 'origin/master'
Avoid resize being called twice at app start, LWJGL.

Display.wasResized() returns true the first time through the game loop.
Refactoring for viewports.

#1504
Merge branch 'origin/master'