js/CGP: Disable page refesh when scrolling or zooming a graph

When scrolling or zooming a graph we want to disable the page
refresh because we are trying to look at the detail. Unfortunately
Javascript cannot override the refresh meta tag;

<meta http-equiv="refresh" content="{$CONFIG['page_refresh']}">

Except with a window.stop() which is brutal but since the
complete RRD data has already been read this is not an issue.

See issue #139 suggesting submitting a PR to refresh RRD data
whilst a graph is scrolled or zoomed.

js/CGP.js

@@ -20,6 +20,7 @@ var CGP = (function() {
             } catch (ex) {
                 console.error('mouse_move:', ex, ex.stack);
             }
+            window.stop();
         }
     };
     var mouse_up = function(e) {
@@ -55,6 +56,7 @@ var CGP = (function() {
             } catch (ex) {
                 console.error('mouse_scroll:', ex, ex.stack);
             }
+            window.stop();
         }
 
         if (e.stopPropagation)