Correct comments.
Derive from GContainer class and review interface.

The class now derives from the GContainer class. The full container interface has been implemented and the interface has been globally reviewed.
Derive from GContainer class and review interface.

The class now derives from GContainer and implements all container class interfaces. Nodes are now passed by reference and cloned internally. This gives full and save memory management to the XML classes.
Import GContainer as now some classes derive from it.
Restructure file (no code change)
Adapt to new GXml and GXmlNode interface.