encoding: Deprecate xmlByteConsumed

This was only used by Chromium/WebKit to detect whether xmlParseContent
really succeeded. It's a horrible, overcomplicated hack.

See 8c5848bd and #767.

include/libxml/parser.h

@@ -1347,9 +1347,7 @@ XMLPUBFUN xmlParserInputPtr
 					 const char *ID,
 					 xmlParserCtxtPtr ctxt);
 
-/*
- * Index lookup, actually implemented in the encoding module
- */
+XML_DEPRECATED
 XMLPUBFUN long
 		xmlByteConsumed		(xmlParserCtxtPtr ctxt);