[Edserplo_users] Update: Event handling

[Steve Loch]

I've disabled the event handler which Rashid put in as I think it is implicated in some of the problems (deadlocks - freezing, etc) we've been having. 

This means that events older than a second are not rejected as previously. With large data sets this can very annoying because while you keep your finger down on a key a large number of events get queued and if the plotting is slow they can take a long time to get actioned - and there's nothing you can do about it. 

If you still get occasions where the display freezes I want to know - thanks.

The good news from the programming point of view is that we are in a position where one example of thread deadlock in Edserplo can readily be generated and therefore investigated. 

Steve