Update SIXX to use latest stable XMLParser

[marianopeck]

I have kindly asked Martin if he could implement that.

Below is his original answer to me:

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This should work (same test results as before), though the character and string formats have changed a little, so you might not be able to read existing serialized objects. The old format Dale chose for encoding non-byte chars violated the XML spec. And I removed the #encodeAsUTF8 stuff. This needs to be done at the entity level (ie, document-wide), not at the element level.

SIXX should now handle decoding automatically when reading, but don't use encodings other than UTF-8, since SIXX generates xml declarations with 'encoding="utf-8"' attributes.

To encode SIXX output, you need to wrap the write stream you're using with an XMLEncodingWriteStreamAdapter and a XMLStreamConverter. The latest XMLParser has an #encodingOn: convenience method for this:

    (XMLUTF8StreamConverter encodingOn: stream). "returns a wrapped stream"

same thing:

    ('utf-8' asXMLStreamConverter encodingOn: stream).

GsFiles are supported too.

Update the ConfigurationOf to depend on #stable smalltalkhub.com PharoExtras/XMLParser.

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I very much agree with what he did. And even if it might break materialization of existing files, I believe its totally worth. Until now, SIXX was using an INCREDIBLE OLD GemStone-specific XMLSupport package that nobody maintained. XML has evolved other the years and Pharo code is a million years ahead. With these changes, SIXX can now use the Pharo's up to date XMLParser, which is super cool.