[Chart] Grid usage

[Sacha Sokoloski]

First of all, thanks for continual updates regarding GSoC progress. 
Looks exciting!

Something that's been bugging me for a long time with chart is the 
'Grid' module. Perhaps I'm simply not using it correctly, but in 
general, it seems like there's something going on behind the scenes with 
respect to adjusting the size of the individual layouts. The point is 
that I even for some simple 2x2 layout of renderables, the widths and 
heights of the individual renderables is rarely equal when rendered as a 
grid. I end up having to adjust things manually using the 'weights' 
function in order to approximate a regular collection of boxes.

Am I not understanding something?

Thanks for any tips,

  - Sacha