- The ephy_shell is passed in a very ugly way: it's set on the module only for
  the duration of function calls. This is because we *can't* let Python keep a
  reference to the shell -- if we did, Epiphany would never close because the
  extension is only unloaded when the shell is finalized.

  A possible fix is to set use PyImport_ImportModuleEx, passing ephy_shell in
  the globals. But then we need to remove it immediately... and what happens
  when we call PyImport_ReloadModule?
