Added WatchdogToken.SpecialDispensationFactor for longer-running work to avoid hang detection triggering prematurely. Set it to 6 for loader (so 60s is the default now) and left as 1 for render, updater and sound processes (so 10s as before which ought to be plenty). A load of documentation on WatchdogToken.SpecialDispensationFactor and WatchdogToken.Ping has been added too.
git-svn-id: http://svn.uktrainsim.com/svn/openrails/trunk@2629 a9f3cfff-6c41-7446-b0ca-052bd761e6eb