Added a StopLoad method. Work for 13374 and landing of new session history/ uriloading. r=mscott a=jevering

docshell/base/nsIDocShell.idl

@@ -73,6 +73,12 @@ interface nsIDocShell : nsISupports
 	[noscript]void loadURIVia(in nsIURI uri, in nsIPresContext presContext, 
 		in unsigned long adapterBinding);
 
+	/*
+	Stops a current load.  This simply stops the network portion of the load.
+	If you wish to do a complete stop, then you should us the
+	nsIWebNavigation::Stop() method. 
+	*/
+	void stopLoad();
 	/*
 	Sets the current document to the one being passed in.  This will simulate
 	a load.