XML Parser enhancement

[thi4go]

The featureIDE eclipse plugin can generate some header / footers that doesn't interest us, as we want only what's within and , for the time being.

Right now, we parse those extra lines with the parseHeader and parseFooter options, which parse literal strings.

Problem: the parser fails when the header/footer has more options generated from the plugin than what we put on our literal strings while parsing.

Solution: manage those variabilities on parseHeader and parseFooter methods, so that the parser doesn't break. Possibly using a parser combinator to handle error, or to literally ignore strings.

https://hackage.haskell.org/package/parsec-3.1.13.0/docs/Text-Parsec.html