"panTo should use tween if new center is in the current bounds + a ratio".

Add a bounds.scale method (takes a ratio and an optional center) and 
call it from the panTo to give a ratio we can pan inside of. Patch by
sbenthall, r=me,elemoine (Closes #1341) 


git-svn-id: http://svn.openlayers.org/trunk/openlayers@7678 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Map.js

@@ -196,6 +196,13 @@ OpenLayers.Map = OpenLayers.Class({
      */
     zoom: 0,    
 
+    /**
+     * Property: panRatio
+     * {Float} The ratio of the current extent within
+     *         which panning will tween.
+     */
+    panRatio: 1.5,    
+
     /**
      * Property: viewRequestID
      * {String} Used to store a unique identifier that changes when the map 
@@ -1368,7 +1375,7 @@ OpenLayers.Map = OpenLayers.Class({
      * lonlat - {<OpenLayers.Lonlat>}
      */
     panTo: function(lonlat) {
-        if (this.panMethod && this.getExtent().containsLonLat(lonlat)) {
+        if (this.panMethod && this.getExtent().scale(this.panRatio).containsLonLat(lonlat)) {
             if (!this.panTween) {
                 this.panTween = new OpenLayers.Tween(this.panMethod);
             }