[merge request] New command 'maximize-discard'

[Teika Kazura <teika lavabit com>]

Please merge my branch. It includes a new command 'maximize-discard'
which treats a maximized window as not maximized, so that
you can resize and move it. Let me explain the discussions in the
mailing list which inspired this command.

As Chris and Timo pointed out in the messages 9 - 13 Oct, 2009,
windows touched by maximize-fill-window-* are not movable nor
resizable, since they receive max'n flag. They don't like this
situation.

Janek wants to halve a max'd window, but it was not possible, either.

Regards,
Teika (Teika kazura)