Changed concat implementation

Author: x7airworker

src/main/java/org/javawebstack/abstractdata/AbstractArray.java

@@ -361,9 +361,7 @@ public boolean equals(Object obj) {
     }
 
     public AbstractArray concat(AbstractArray array) {
-        for (AbstractElement element : array)
-            add(element);
-
+        elements.addAll(array.elements);
         return this;
     }
 }