Prevent an NPE when referencing Image.AcquisitionDate

The acquisition date is now optional, and so may be null.  Without this
commit, bfconvert threw an NPE when the acquisition date was missing,
and the automated data tests logged a warning for each missing date.
Volocity: flag most files as being pixels files

This is the second part of the fix for #12485.  This should speed up
import time and assist in preventing MemoryLimitExceptions for large
Volocity filesets.
Modify bfGetPlane and bfsave to use the inputParser
Add unit tests for input parsing
Merge pull request #1269 from sbesson/12462_inputParser

Extend usage of inputParser in Bio-Formats MATLAB
Merge pull request #1267 from melissalinkert/volocity-companion-files

Volocity: flag most files as being pixels files
Merge pull request #1264 from melissalinkert/date-npe

Prevent an NPE when referencing Image.AcquisitionDate