Using bin number

Using bin number is better because then we will not get rid
of old tiles from rendering.
Clean up the code some
Updated VGL to use wheel events
Implemented mouse wheel
Removed debug messages
Hide tiles if they are loaded and zoom level does not match
Apply speed up factor for zooming using right mouse button
Updated VGL
Fixed render window not found
Added option to enable draw on asyc resource load
Fixed a bug where only mouse wheel zoom does not load tiles
Merge pull request #72 from OpenGeoscience/improve_tile_somemore

Improve tile somemore