made galileo_utils handle formatting the hostname for get_hostname method. this is worse for error handling but seems better overall, otherwise the user has to do string processing like take the newline off the end of stdout and make sure the hostname is formatted to end in .local
added a TODO in lib/app.js
when we are on the Home Page, tell the user the hostname. the client side finds it using window.location.hostname
warn users that they will need Bonjour
detect user OS and show them messages about Bonjour / Zeroconf / Avahi accordingly
reformatting Home Page slightly