[Paraview] vtkSMCollaborationManager::FollowUser(id) doesn't update view

[Utkarsh Ayachit]

I am going to limit my responses to technical parts. It's too early in
the morning for anything else :).

> Yes, all these timer loops in paraview are annoying.

I am not sure there "many" timer loops in ParaView. Please feel free
to elaborate. Even this collaboration timer comes into play only when
connected to a collaboration enabled session. Also, not collaboration
support is one of those advanced, not often used features and hence
the road is expected to be bumpy.

> There is no platform
> independent solution for registering callbacks on sockets, but for each
> supported OS a clean solution exists, which you could implement. So, it is
> doable,

Having the event loop calling select on the socket is a fairly common
practice esp. in single threaded applications.