Fixed stupid subclassing bug (and added test to avoid that in the future)

RSXML/RSXMLParser.h

@@ -51,8 +51,6 @@
 + (BOOL)isOPMLParser;
 /// @return @c YES if parser supports parsing HTML files.
 + (BOOL)isHTMLParser;
-/// Keeps an internal pointer to the @c RSXMLData and initializes a new @c RSSAXParser.
-- (instancetype)initWithXMLData:(RSXMLData * _Nonnull)xmlData;
 /// Will be called after the parsing is finished. @return Reference to parsed object.
 - (id)xmlParserWillReturnDocument;
 @end
@@ -61,6 +59,8 @@
 @interface RSXMLParser<__covariant T> : NSObject <RSXMLParserDelegate, RSSAXParserDelegate>
 @property (nonatomic, readonly, nonnull, copy) NSString *documentURI;
 
++ (instancetype)parserWithXMLData:(RSXMLData * _Nonnull)xmlData;
+
 - (T _Nullable)parseSync:(NSError ** _Nullable)error;
 - (void)parseAsync:(void(^)(T _Nullable parsedDocument, NSError * _Nullable error))block;
 - (BOOL)canParse;