Use HTMLOrderedDictionary when cloning element's attributes

Sources/HTMLOrderedDictionary.m

@@ -154,4 +154,11 @@
 	return [_keys countByEnumeratingWithState:state objects:buffer count:len];
 }
 
+#pragma mark - Copying
+
+- (id)mutableCopy
+{
+	return [[HTMLOrderedDictionary alloc] initWithDictionary:self];
+}
+
 @end

Sources/include/HTMLDOM.h

@@ -24,3 +24,5 @@
 #import "HTMLKitDOMExceptions.h"
 #import "HTMLNamespaces.h"
 #import "HTMLQuirksMode.h"
+
+#import "HTMLOrderedDictionary.h"

Tests/HTMLKitTests/HTMLNodesTests.m

@@ -543,6 +543,18 @@
 	XCTAssertEqualObjects(clone.firstChild.firstChild.asElement.attributes, innerLevel2.attributes);
 }
 
+- (void)testDeepCloneElementAttributes {
+	HTMLElement *div = [[HTMLElement alloc] initWithTagName:@"div"
+												   attributes:@{@"id": @"outer",
+																@"class": @"green",
+																@"data": @"test"}];
+
+	HTMLElement *clone = [div cloneNodeDeep:YES];
+
+	XCTAssertEqualObjects(clone.attributes, div.attributes);
+	XCTAssertTrue([clone.attributes isKindOfClass:[HTMLOrderedDictionary class]]);
+}
+
 #pragma mark - Bug Fixes
 
 - (void)testBugFix_Issue_20 {