NimForum 2.2.0 - Fixes a big CVE!

[cblake]

The random "logging people out" bug is also pretty annoying. { I get some 
session timeout, but it's clearly not scheduled as sometimes it takes many days 
and others only many seconds... ;-) I know it's not just me since @mratsim 
mentioned it a very long time ago..so, at least 3, me + him + who he mentioned 
it to. }