ScoringSystem should be subclasses and not instance

[pombredanne]

ScoringSystem should be subclasses and not instance IMHO as this much better capture the essence of theses. Eventually a Score may be a better way and is highly similar to a version like in univers. In particular I want to be able to sort from high to low score and "medium", "high", and "low" cannot be sorted naturally implicily and needs some code for this.

[Hritik14]

UNISCO