Refs #10069.  Corrected run end and log end.

1. Run end time is redefined in order not to miss the events in last
pulse;
2. Time series property is extended to run end;

On branch feature/10069_improve_geneventfilter
  (use "git reset HEAD <file>..." to unstage)

      modified:   ../Mantid/Framework/Algorithms/inc/MantidAlgorithms/GenerateEventsFilter.h
      modified:   ../Mantid/Framework/Algorithms/src/GenerateEventsFilter.cpp
      modified:   ../Mantid/Framework/Algorithms/test/GenerateEventsFilterTest.h
Fixed a bug due to inaccurate run end time in log. Refs #10069.
Refs #10069.  Improved some documention on properties.
Merge remote branch 'origin/feature/10069_improve_geneventfilter'