Added support for error messages & fixed bugs:

- parserClassForXMLData: did return instance instead of class
- DateParser: array index typo

RSXML/RSFeedParser.h

@@ -16,6 +16,9 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
+static NSString *kLIBXMLParserErrorDomain = @"LIBXMLParserErrorDomain";
+static NSString *kRSXMLParserErrorDomain = @"RSXMLParserErrorDomain";
+
 BOOL RSCanParseFeed(RSXMLData *xmlData);