Add TLS support and Facebook chat demo (only for firefox)

Add TLS support and a Facebook chat demo.  This only works for Firefox for now, and will break Chrome until chrome.sockets.tcp.setPaused is updated (https://code.google.com/p/chromium/issues/detail?id=403076).
I was able to get it to work in the google case for a delegated account, which is because the host is already forced in https://github.com/freedomjs/freedom-social-xmpp/blob/master/firefox-google-demo/lib/view_googleauth.js#L89

It looks like the srv records in xmpp (http://wiki.xmpp.org/web/SRV_Records) are essentially cnames to the correct server. It seems like the DNS lookup should do its thing and return the domain name of the delegated server. Hopefully that's what resolveSrv does belows this, and we're just skipping the part that resolves the names to numbers :)