Epoch to milli mapping is inaccurate if version can't be ascertained

[tcj]

If the parser can't find a SHA in the SYS CSVs, it can't discern a version.

If it can't discern a version, it doesn't process SST lines.

Perhaps this could be adjusted:

                    #
                    # If SST file, map millis onto epochs
                    if Suffix == 'SST':
                        if compatibility_version < 3:
                            lines = process_sst_lines(lines, fqfn)

[tcj]

The net result is that sst.csv may contain dates in the year 2080, etc.