i3/tmux/zsh/bash/emacs: Use emacs daemon

Run an emacs daemon at i3 startup time.  Use emacsclient for all emacs
access.  Ensure the emacsclient passes and empty --alternate-editor
value so that it will force a new daemon to start if it isn't there
for some reason.

Signed-off-by: Ben Walton <bdwalton@gmail.com>