Fixed: crash on -CPArray/CPDictionary description if a value was the window object.

Without this fix, code like `[@{ "a": window } description]` would crash with a "Maximum call stack size exceeded" exception.

Now`CPDescriptionOfObject()` function simply describes the window object as `window` rather than trying to serialise it into a huge description string.

Foundation/CPObject.j

@@ -544,6 +544,9 @@ function CPDescriptionOfObject(anObject)
     if (anObject === undefined)
         return "undefined";
 
+    if (anObject === window)
+        return "window";
+
     if (anObject.isa)
     {
         if ([anObject isKindOfClass:CPString])

Tests/Foundation/CPDictionaryTest.j

@@ -389,7 +389,7 @@
 
 - (void)testJSObjectDescription
 {
-    var dict = [[CPDictionary alloc] initWithObjects:[CGRectMake(1, 2, 3, 4), CGPointMake(5, 6)] forKeys:[@"key1", @"key2"]],
+    var dict = @{ "key1": CGRectMake(1, 2, 3, 4), "key2": CGPointMake(5, 6) },
         d = [dict description];
 
     [self assertTrue:d.indexOf("(1, 2)") !== -1 message:"Can't find '(1, 2)' in description of dictionary " + d];
@@ -399,6 +399,15 @@
     [self assert:'@{\n    @"key1": @[\n        @"1",\n        @"2",\n        @"3"\n    ],\n    @"key2": @"This is a string",\n    @"key3": @{\n        @"another": @"object"\n    }\n}' equals:[json_dict description]];
 }
 
+- (void)testWindowJSObjectDescription
+{
+    var dict = @{ "Key": window };
+
+    // 'window' is the global namespace so we should never try to fully describe it. If we do, we're likely
+    // to get into an infinite loop, and even if we don't it'll be huge.
+    [self assert:'@{\n    @"Key": window\n}' equals:[dict description]];
+}
+
 - (void)testInitWithObjectsAndKeys
 {
     var dict = [[CPDictionary alloc] initWithObjectsAndKeys:@"Value1", @"Key1", nil, @"Key2", @"Value3", @"Key3"];