Grid view - code review

Hi Sune,

I'm now quite confident that the code is doing what it's supposed to, but still want to add unit tests for the grid view before this gets merged down.

However it'd be nice to have a second pair of eyes on the code as is, as there probably is some performance degradation due to more calculations. Would you be up for that? And if you are interested in also submitting some code to this branch, could you perhaps allow me to push the branch to your repo?

For the future - it might be nice to refactor knockout.list as it's starting to feel messy imo. I'll create another issue on that.

/maarten