Refs #10182.  Made minor changes to algorithms related.

  better log information
  more output to investigate the experiment data
  enabled user to specify the precision of offset value
  enabled to accept frequency's name and unit used for VULCAN
  added one property to specify tolerance to compress events
Fixed a bug. Refs #10182.
Refs #10182.  Added algorithm to save GSAS file for VULCAN.

On branch feature/10182_reduce_vulcan
Changes to be committed:

      new file:   ../Mantid/Framework/PythonInterface/plugins/algorithms/SaveVulcanGSS.py
      modified:   ../Mantid/Framework/PythonInterface/test/python/plugins/algorithms/CMakeLists.txt
      new file:   ../Mantid/Framework/PythonInterface/test/python/plugins/algorithms/SaveVulcanGSSTest.py
Added methods to write VULCAN-required header. Refs #10182.
Refs #10182. Added documentation.

On branch feature/10182_reduce_vulcan
Changes to be committed:

modified:   ../../Code/Mantid/Framework/DataHandling/src/SaveGSS.cpp
- changed a log level.
modified:   ../../Code/Mantid/Framework/PythonInterface/plugins/algorithms/SaveVulcanGSS.py
- minor changes
new file:   ../../Code/Mantid/docs/source/algorithms/SaveVulcanGSS-v1.rst
- documentation
new file:   UsageData/vdrive_log_bin.dat
- test data
Tried to fix error in doc. Refs #10182.
Fixed doc test. Refs #10182.
Cleaned the doc. Refs #10182.
Removed some debugging output. Refs #10182.
Merge remote branch 'origin/feature/10182_reduce_vulcan'