emacs: add launchd plist for server daemon.

Since emacs version 23.1 the emacs executable accepts a --daemon flag
which will start emacs as a server daemon. You can then connect to the
server using emacsclient (reducing startup time etc).
See http://www.emacswiki.org/emacs/EmacsAsDaemon#toc7
emacs: update 24.4 bottle.

Closes #33455.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>