Get username from session file.

Logging into galaxy doesn't return username in response.
error handling and loading time cleanups
Adapt webapp to the requiresAuth world.

No more special case for admin apps; all apps have their proxy configurations
specified in their appConfig. webapp passes through the requiresAuth flag.
Log out of galaxies too, not just Meteor Accounts.
Allow extra http headers to be specified on DDP.connect.

Only works on server-to-server DDP (websockets clients) right now, which is a
little weird. I can't figure out if sockjs allows us to specify extra headers.
Minor webapp cleanup
Replace ssh tunnel deploy with cookie-based auth.
Allow galaxy to not exist when deploying
Account for galaxy discovery failure when trying to revoke old tokens.
Add accounts-meteor and meteor-auth packages.

There's a big ugly hack here to get around the fact that our meteor accounts
oauth server doesn't allow query parameters in redirect_uris. We should probably
just make it support them.
Compute proper OAuth state for Galaxy. Use correct method (GET) for redirect.
Rename Oauth.initiateLogin to Oauth.showPopup.
Temporarily hardcode that panel http does not require auth
add package 'cookies' (internal for now)
Switch from URI to base64 encoding of oauth state
Temporarily save off the URLs of sockjs connections.
Preserve query string when sending /websocket urls to sockjs.
Update meteor tool to new /authorize url
Implement Meteor.server.onConnection and SessionHandle.
Remove remaining references to login token from livedata.