Improve 2 column layout

[lisbethmarianne]

The 2 column layout looks a bit messy to me and is different in different browsers. There is only one column for closed events. There is a gap on the second column in Chrome/Safari.

I think we should think of changing this again.

Firefox:

Chrome:

I'm not posting pictures of the admin area, but this look also not ideal to me. Maybe we should put the upcoming boxes on one side and the past on the other side or the upcoming on top and the past on the bottom?

[lisbethmarianne]

I did some fixes, but I think we should maybe not use CSS multi-column layout. It behaves totally different in different browsers.

One problem, I have no idea how to fix, is that the new page has some extra space at the bottom in Chrome.