(Issue430) Added graceful shutdown for express, mq and activity
Merge branch 'master' into issue-430

Conflicts:
	node_modules/oae-util/lib/mq.js
	node_modules/oae-util/lib/server.js
Fixing potential double-callback when queue fails to bind
Merge pull request #430 from mrvisser/issue-430

Shutdown lifecycle
Default group joinability to 'managers add people', return text/plain when responding to file upload (IE9 does not support application/json returns on upload).
Added some docs
Etherpad integration