this commit adds the ability to read the sameAs attribute of portal.json

portal.sameAs is an array of portal dat:// addresses that state that
this portal is the same as those portals, and that we should load their
messages under our name

this makes it possible to effectively post to the same account from
different machines

note: port_1 needs to have port_2 in its sameAs array, and port_2 needs to
have port_1 in its sameAs array, i.e. the relationship needs to be mutual

this adds a bit of kludge to portal.js, but it was the simplest way i
could see of making it possible to render the same icon for remotes
as the source of the remotes

Add very basic "event" handling in Portal.js; Build sameAs on it

for each portal in sameAs, we add their list of ports to
our feed

has_hash should maybe have some harder checks, what happened was
this.json.sameAs didn't exist but has_hash still went through (kinda strange)
and so the resulting bool wasn't a bool, but undefined!