Fix use of dispose in ol.parser.KML
Fix use of dispose in ol.control tests
Fix use of dispose in ol.control.ZoomSlider tests
Fix use of dispose in ol.layer.Layer tests
Fix use of dispose in ol.layer.Vector tests
Fix use of dispose in ol.Map tests
Fix use of dispose in ol.renderer.webgl.ImageLayer tests
Merge pull request #643 from twpayne/fix-dispose

Fix dispose