Merge pull request #30 from frankbille/master

Release 1.3
Merge pull request #33 from frankbille/master

Release 1.4
Merge pull request #35 from frankbille/master

Release 1.5
Calculating rating for drawn matches as 25% of KFactor
Merge pull request #37 from frankbille/drawnGames

Merge the pull request for games that ends in a draw.