Added analytics dispose()

modules/statistics/AnalyticsAdapter.js

@@ -115,6 +115,15 @@ class AnalyticsAdapter {
      */
     dispose() {
         logger.warn('Disposing of analytics adapter.');
+        
+        if (this.analyticsHandlers && this.analyticsHandlers.length > 0) {
+            this.analyticsHandlers.forEach(handler => {
+                if ( typeof handler.dispose === 'function' ) {
+                    handler.dispose();
+                }
+            });
+        }
+        
         this.setAnalyticsHandlers([]);
         this.disposed = true;
     }