Fixing namespace prefixes in outline.el

[Oleh]

Hi all,

As I was looking to improve the patch in
http://debbugs.gnu.org/cgi/bugreport.cgi?bug=19493, I've noticed that
outline.el has some really outdated stuff, like function names without
prefixes, and plain text instead of "\\{outline-mode-map}" in the mode
definition.

Is it OK to e.g.:

    (defun outline-show-subtree ()
      "Show everything after this heading at deeper levels."
      (interactive)
      (outline-flag-subtree nil))

    (define-obsolete-function-alias
        'show-subtree 'outline-show-subtree "25.1")

Also, what's the opinion on the indentation with tabs and spaces?
Encouraged / discouraged / don't care? I very much prefer spaces only.

regards,
Oleh