GuessIt Integration

After some discution with @gazpachoking, and because we don't need to reinvent the wheel, we should integrate https://github.com/wackou/guessit. It's a python library that can parse a maximum of information from series and movies filenames. It seems to be used in some other download related projects, like CouchPotato.

The main objective is to find series and movies titles more reliably, but also additionnal informations like episode and season numbering, languages, etc...

I have already made some pull requests on guessit project to fix some small issues.