BasicDragger.java Bug Fix

[faa]

Hi,

I was working with Dzuy and Matt on this issue. The cursor was moving off of the ground symbols while dragging when zoomed in. I wrote up the fix for the ground symbols.

Thanks.

[mbudk]

I still have issues using this version (symbol not following mouse cursor). It seems like a regression in BasicDragger. Using versions prior to svn version 649 works (e.g. rev 459). See old svn repo: https://worldwind31.arc.nasa.gov/svn/trunk/WorldWind/src/gov/nasa/worldwind/util

EDIT: created my own pull request #20

[zglueck]

Thanks @faa for contributing your work in this pull request. We've conducted a comprehensive refactor of the BasicDragger to correct the behavior which is detailed in commit f67dee9. The new approach provides a Draggable interface which moves drag execution to the object itself. We've also provided utility methods which correct the behavior observed in the DraggableSupport class. All World Wind objects implementing Movable or Movable2 have also incorporated Draggable and the appropriate utility functions which correct the erroneous dragging behavior. Again, thanks for providing your approach and we hope the new interface serves you well.

[faa]

@zglueck Thanks, I will pull down the latest code and try it out.