Payloads: add the SPASpec payload
Sidebar: migrate all the signin/signout to the sidebar
Worker: remove all of the signin/signout code from the worker
Sidebar: make the SPA setup persistent
Fix tests
Add payloads to jshint global list for sidebar
Make the users list only contain those users that are actually present, rather than both present and disconnected
Server: make the SESSION_SECRET error more explicit
Makefile: merge runserver_dev and runserver targets

Now there is only the runserver target:

    make runserver # development
    NODE_ENV=production make runserver #production mode

Also this patch takes care of setting a default SESSION_SECRET for development
mode. But if we launch the server in production mode without explicitly setting
SESSION_SECRET, it will raise an error. The intent is to prevent setting a dumb
secret without noticing it.
Payloads: add JSDoc for each payload
Remove the present functionality from the users list as it is now obsolete.
Fix tests
Merge branch 'master' into remove-harcoded-login

Conflicts:
	static/js/spa/server.js
	test/frontend/spa/server_test.js
Upgrade node to 0.10.x
Toggle help bubble message between Mute and Unmute microphone
Reset the session cookie on signout.
moved the load test from https://github.com/tarekziade/talkilla-loadtest
added an example + typo/phrasing
Makefile: put a deprecation warning for the runserver_dev target
Remove User#present