Menu style, experimental

I've updated the branch that @scottgonzalez started. I didn't change much, mostly adding two multi-line items to be able to visually compare single and multi line items.

I also noticed that menu-items ended up with a text-cursor, caused by the removal of anchors. I've fixed that by explicitly setting cursor:pointer. If we end up not using this branch, I can cherry-pick that commit to master.

Mostly looking for someone to verify that this new style is actually better then the old one. This is now much more similar to the menubar menus in OSX, which we used a lot as a reference for menu. Though maybe we also need to get of the borders, along with the margin: -1px 'hack' that we currently have.