Stylistic refactoring: stop using <table> for weird purposes

* box and lightly color some forms
* some h3s -> h2s
Extract title/h1 text to function
Condense and add silly decorations/styling to page header

* move logged-in status and logout link together to top right, above nav
  bar
* get rid of the floating-ness of the countdown and title and reduce
  their margins; they usually won't touch anyway, and if they do then
  (I think) it makes more sense to save screen space
* distinguish the wiki link from the others, since it's not inside
  Puzzletron (i.e. I keep accidentally clicking on it while testing on
  localhost and getting diverted to example.com)
* :hover background color changes! gradients! border radii! (using the
  CSS3 spec with no attempts at compatibility, since this is rather
  frivolous)