New TileManager

This removes all tile queueing/loading specific code from Layer.Grid
and creates a new class that manages tile loading and caching.

tests/deprecated/Layer/MapServer/Untiled.html

@@ -5,9 +5,6 @@
     <script src="../../../../lib/deprecated.js"></script>
     <script type="text/javascript">
 
-    // turn off animation frame handling, so we can check img urls in tests
-    delete OpenLayers.Layer.Grid.prototype.queueTileDraw;
-
     var isMozilla = (navigator.userAgent.indexOf("compatible") == -1);
     var layer;