Prevent endless loop when call JSROOT.parse second time

If object has cross-references, parse methods caused endless recursion

Author: linev

scripts/JSRoot.core.js

@@ -919,6 +919,9 @@
             return; // pair object is not counted in the objects map
          }
 
+        // prevent endless loop
+        if (map.indexOf(value) >= 0) return;
+
          // add object to object map
          map.push(value);