Refactoring the default theme (for great justice)

[stevenleeg]

So the current state of the default theme is terrible. The CSS is a mess, the HTML is a mess, and it was all hacked together when I was just trying to get a MVP running.

Things are different now. We have the technology to make this a lot better, so that's what this PR is set out to do. Here's what I'm planning:

• [ ] Rewrite all of the default theme templates using skeleton.css. (These subtasks are somewhat ranked by priority)
  • [x] base.html
  • [x] index.html
  • [x] board.html
  • [x] thread.html
  • [x] post_editor.html
  • [x] user.html
  • [x] user_settings.html
  • [x] login.html
  • [x] register.html
  • [ ] admin.html
  • [ ] admin_users.html
  • [ ] admin_user.html
  • [ ] admin_boards.html
  • [ ] action_move_thread.html
• [x] Redo all of the CSS in SASS, so it's remotely reasonable to work with/maintain.
• [x] Make the original theme easier to use/overall less jank as fuck.
• [x] Make the site responsive, so it doesn't look like donkey shit on phones and tablets.

:beer:

[stevenleeg]

So the only tasks left are admin pages. These are pretty low priority right now, so I'm going to go ahead and merge these in anyways, as this PR has taken me way too long as it is. These will be fixed in the near future.