On-Open Validator broken for TSV7 files

[elsylambert]

The "on open" validation was intended to be a fast check of certain features to prevent it from being used, since it would likely crash tc-create. Those checks are:

Does it have the correct header? Does every row have the correct number of columns? If not report whether too few or too many. Are all ID values unique? Report all duplicates and their row numbers. It may check for:

empty rows (which would be also be a too few columns issue, but perhaps a different root cause worth reporting)

For TSV 7 files, this is broken and the app crashes when the header is bad. It does not report duplicate IDs.

[elsylambert]

Looks good in translationCore Create - v1.8 build 197-7a6b5de. On-Open CV reports errors when master/target file has a bad header or duplicate id.