Improve tabs appearance on Twenty Thirteen and other themes that add padding to ul
Whitespace
Improve Trashed Doc workflow

- Allow site admins and Doc authors to access the single-Doc view of Docs
  that are in the Trash
- Provide "Remove from Trash" links in Docs directory and on single-Doc pages,
  to enable front-end removal from the trash

Fixes #370

Props @dcavins for the help with this issue