color status patch: Get a colorized status bar in mutt

Patch from https://thomas.glanzmann.de//mutt/#cstatus

Original-author: Thomas Glanzmann <thomas@glanzmann.de>
Signed-off-by: David Sterba <dsterba@suse.cz>

Note: lightly tested, the example color setup from the page worked; the code diverged a bit so the statusbar does not look exactly the same, eg. the "--" are missing as they're now filling the whole line.