Adds explicit flex-direction.
Removes unnecessary comment.
Modifies list grids to provide maximum support.

Sadly, Safari didn't implement box-lines: multiple. Therefore it's
impossible to support "old" webkit (non-chrome) until Apple fully
supports the new flex model. Until that happens, webkit "automatically"
has .list-grid-static applied which leads to a left-aligned grid.

It may be possible to remove all references to the webkit-box model,
since lines: multiple isn't supported anyways, I'm leaving it in though
in case Apple doesn't adopt the flexbox standard.