Clean-up of iFatras::ProcessSamplingTool
The iFatras::ProcessSamplingTool::interact
methods were not called by any clients, so have been removed.
This allowed substantial simplification of the iFatras::ProcessSamplingTool
class itself.
It was then clear that it could be made thread-safe by passing a CLHEP::HepRandomEngine
pointer as an argument to the remaining processSample
method rather than holding a member variable.