Restore maxZoomLevel functionality, removoed between rc1 and rc2 by Erik.

This was the *only* way of setting zoom levels up until 2.0, taking it away
in an RC release is bad. (This resolves Jeff Dege's most recent mail to the
users list.)


git-svn-id: http://svn.openlayers.org/branches/openlayers/2.0@1348 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer.js

@@ -182,6 +182,9 @@ OpenLayers.Layer.prototype = {
           'minExtent', 'maxExtent',
           'numZoomLevels'
         );
+        if (this.map.maxZoomLevel && !this.numZoomLevels) {
+            this.numZoomLevels = this.map.maxZoomLevel + 1;
+        }
         for(var i=0; i < properties.length; i++) {
             if (this[properties[i]] == null) {
                 this[properties[i]] = this.map[properties[i]];