Add a method to SVGKImage to tell if there is a CALayerTree already inited.
Autorelease objects being assigned instead of creating a temporary object, assigning the temporary object, then releasing the temporary object.
Use initWithBytes:length:encoding: in NSDictionaryFromLibxmlAttributes instead of creating a temporary string to store the string in.
Also use NSString's initWithBytes:length:encoding on handleFoundCharacters:length:
Passing self in libxml so we don't have to worry about two parsers running at once.