[css3-gcpm] 1gr + 1gr != 2gr? Grrrrr...

I find it a little odd that 1gr + 1gr is not equal to 2gr. I think I  
see the point, but making the size of a unit change depending on  
whether it is even or odd seems ... confusing. Perhaps there could be  
some other way of saying "include/don't include the column gap in  
this calculation".

--Brady