XML File for Carrot2

[Quoniam]

Some characters in text (abstrats, descriptions, claims) make a non correct XML file to be use by Carrot2

&,<,>
Sure, but may be others, they are seen as an XML control character, so all of this control characters are to be treated

[cvanderlei]

Do anybody have any suggestion how to identify the others characters to be treated?

[rfaga]

@cvanderlei
I think we could use standard lib xml.sax to escape all inserted xml content:

https://wiki.python.org/moin/EscapingXml

I sent a possible fix on 1db5544 , but need more tests