Sanitize buffer display handling in simple.el.

Sanitize buffer display handling in simple.el.

* simple.el (goto-line, compose-mail-other-window): Replace
switch-to-buffer-other-window by pop-to-buffer-other-window.
(pop-global-mark): Use pop-to-buffer-same-window instead of
switch-to-buffer.
(compose-mail-other-frame): Use pop-to-buffer-other-frame
instead of switch-to-buffer-other-frame.
(special-mode-map): Bind "q" to quit-restore-window instead of
quit-window.