Updating manifest.json (should have been in pull request #19)

Updating manifest.json, this was meant to be in https://github.com/freedomjs/freedom-social-xmpp/pull/19 but I accidentally merged too early (need to get my mind out of perforce land)

The real change here is that I updated the key and client_id to match UProxy.  Also I changed the tabs to indents, so the diff may look like more lines have changed.