Quit cider popup buffers with 'append argument

  The default behavior of `quite-window` is to remove the buffer from the
  selected window's buffer history. We want to use the 'append action instead of
  'bury to preserve the buffer in the history to allow future invocations of
  `display-buffer` and `pop-to-buffer` to reuse the window.
Merge pull request #877 from vspinu/quit-append

Quit cider popup buffers with 'append argument