this started out as a "small patch" but grew, it does the following:

* reduce the spacing to just 2px between boxes
* center drawing (should allow for defined aligment? spreading days to take full space?)
* paint borders last (allows for "glow" effects ... cool)
* add a hover effect (innefficient painting atm, will fix)
* make the code a lot clearer by using human readable names for the variables