revamped the encoding support, added iconv support, so now libxml if

* encoding.[ch], xmlIO.[ch], parser.c, configure.in : revamped
  the encoding support, added iconv support, so now libxml if
  compiled with iconv automatically support japanese encodings
  among others. Work based on initial patch from Yuan-Chen Cheng
  I may have broken binary compat in the encoding handler
  registration scheme, but that was so utterly broken I don't
  expect anybody to have used this feature until now.
* parserInternals.h: fixup on the CHAR range macro
* xml-error.h, parser.c: catch URL/URI errors using the uri.c
  code.
* tree.[ch]: added xmlBufferGrow(), was needed for iconv
* uri.c: added xmlParseURI() I can't believe I forgot to
  implement this one in 2.0 !!!
* SAX.c: moved doc->encoding update in the endDocument() call.
* TODO: updated.

  Iconv rules :-)

Daniel

include/libxml/xmlIO.h

@@ -33,6 +33,7 @@ struct _xmlParserInputBuffer {
     xmlCharEncodingHandlerPtr encoder; /* I18N conversions to UTF-8 */
     
     xmlBufferPtr buffer;    /* Local buffer encoded in  UTF-8 */
+    xmlBufferPtr raw;       /* if encoder != NULL buffer for raw input */
 };