TODO LIST
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+ Allow to parse an XML string rather than only an XML file
- Better compliance with DOM specifications.
- Better implementation of XPath (handle attributes)
- Modify save to write <tag>hello</tag> without <cr> when content is short
+ Also save <tag/> when content is empty
+ Add method should return the UID of the newly created node
- Save method should allow for the tree in output in order to save the filename
- Constructor should allow to take a struct in input (using struct2xml.m)
+ There should be an export.m methods to export XML to a simple struct when possible