According to the spec it's necessary to:
1. Layout the cells in the grid
2. Find the sizes of the rows and columns
Since I had started to do this backwards, and as I expand in future
commits, I take here the opportunity to start with a clean state.
The occupation_grid keeps track of which cells in the grid have been
filled out.
This is a really starter attempt at formatting the grid. It doesn't yet
take into account the computed_values of grid-template-rows, nor the
values in grid-column-start and like CSS properties.
But these changes are a start and make it so the examples in
display-grid.html work.
To be fleshed out further..
