add formulae

- autossh
- ssh-copy-id
- mobile-shell (mosh)
- reattach-to-user-namespace (supposed to resolve issues with some
	difftools in tmux)
turn off volume change feedback sound

Note: due to some issue with OSX, it must be turned on THEN off, or
sometimes it will remain on, even though in the prefs it is unchecked,
the lines added should resolve that.
add .zsh bootstrap