fix printing of colors

Hi @zoggy,

The printing of colors seems to be broken. Color channels should be a number between 0 and 255 but they are currently printed as a value between 0 and 1.

The following patch works for me.

EDIT: I also added a fix for the printing of numbers, 3.0 would be displayed as 3. which is not valid CSS. I used %g so that now 3.0 is printed as 3 which is more readable. :-)

Cheers,