maintain graph/grid in the center when detail pane is opened

@dougbradbury @evanShap Please let me know what you think. There's quite a few changes to accomplish this. The biggest disadvantage of this change is that to be able to move the graph as the detailPane is open, I need to remove the graph/grid from the container css class (so now if you decrease the width of the browser, the graph doesn't relocate as before - as the header does). I can show you to see what I mean (difficult to explain)