Fixed a few bugs in CPArray and added many new tests for CPArray.

Reviewed by me.

Foundation/CPArray/_CPJavaScriptArray.j

@@ -2,7 +2,8 @@
 @import "CPMutableArray.j"
 
 
-var indexOf = Array.prototype.indexOf,
+var concat = Array.prototype.concat,
+    indexOf = Array.prototype.indexOf,
     join = Array.prototype.join,
     pop = Array.prototype.pop,
     push = Array.prototype.push,
@@ -172,6 +173,23 @@ var indexOf = Array.prototype.indexOf,
             objj_msgSend(self[index], aSelector);
 }
 
+- (CPArray)arrayByAddingObject:(id)anObject
+{
+    // concat flattens arrays, so wrap it in an *additional* array if anObject is an array itself.
+    if ([anObject isKindOfClass:CPArray])
+        return concat.call(self, [anObject]);
+
+    return concat.call(self, anObject);
+}
+
+- (CPArray)arrayByAddingObjectsFromArray:(CPArray)anArray
+{
+    if (!anArray)
+        return [self copy];
+
+    return concat.call(self, anArray.isa === _CPJavaScriptArray ? anArray : [anArray _javaScriptArrayCopy]);
+}
+
 - (CPArray)subarrayWithRange:(CPRange)aRange
 {
     if (aRange.location < 0 || CPMaxRange(aRange) > self.length)