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.
Remove the present functionality from the users list as it is now obsolete.
Upgrade node to 0.10.x
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
Server: display the mode and the port at startup
Merge pull request #305 from tOkeshu/session-secret-doc-improvement

SESSION_SECRET default setting improvement
Merge pull request #306 from Standard8/node_upgrade

Upgrade node to 0.10.x
Merge pull request #304 from Standard8/server_connected_list

Make the server only retain users that are connected / don't fail on an verified session cookie when connecting long polling