maxResolution not correctly set when initializing map from WMC document, p=trondmm,r=me (closes #3191)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@11733 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Format/Context.js

@@ -269,9 +269,14 @@ OpenLayers.Format.Context = OpenLayers.Class({
      */
     contextToMap: function(context, options) {
         options = OpenLayers.Util.applyDefaults({
-            maxExtent: context.maxExtent,
-            projection: context.projection
+            maxExtent:  context.maxExtent,
+            projection: context.projection,
+            units:      context.units
         }, options);
+        if (options.maxExtent) {
+            options.maxResolution = 
+                options.maxExtent.getWidth() / OpenLayers.Map.TILE_WIDTH;
+        }
         var map = new OpenLayers.Map(options);
         map.addLayers(this.getLayersFromContext(context.layersContext));
         map.setCenter(