bug#1806: dired-pop-to-buffer in wrong place

[martin rudalics]

> I can't image a situation when someone will want to display a narrow
> window on a full-height side window.  At least I think currently we should
> restore the old behavior when these commands displayed a narrow window
> below the original window instead of a side window.

I did this for `dired-pop-to-buffer'.

> I think a general rule of thumb for finding all such cases should be the
> following: when there is a call to `fit-window-to-buffer' after calling
> `pop-to-buffer' then split windows vertically because otherwise
> `fit-window-to-buffer' makes no sense since it adjusts the window height
> and can't do this on a full-height horizontally split window.

Good suggestion. I found the following candidates:

`Electric-pop-up-window', `ibuffer-confirm-operation-on',
`disabled-command-function', `proced-send-signal',
`fancy-startup-screen', `display-time-world', `widget-choose'.

Can someone comment on these?  We might also have to consider windows
affected by `temp-buffer-resize-mode'.  I'll leave it to Carsten to
figure out what's best for `org-mode'.

As for `calendar' I share Stefan's POV ...

martin