Do not show the wxWebView sample tools menu unless a page has been loaded. Originally it crashed but it doesn't make sense to change the zoom or view the source if there is no page loaded.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/SOC2011_WEBVIEW@67787 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/web/web.cpp

@@ -320,6 +320,9 @@ public:
      */
     void onToolsClicked(wxCommandEvent& evt)
     {
+        if(m_browser_ctrl->GetCurrentURL() == "")
+            return;
+
         tinySize->Check(false);
         smallSize->Check(false); 
         mediumSize->Check(false);