Issue with CSV import new heading

[cheesegrits]

As per this thread:

http://fabrikar.com/forums/index.php?threads/bug-server-500-error-when-ignoring-extra-columns-on-csv-import.35048/

If you have extra columns / headings in the CSV, and elect not to create them, the import gets screwed up 'cos we aren't removing the unwanted columns from the actual data array. So it's OK if the unwanted columns are the last columns in the CSV, but if there are any used columns after the unwanted columns, we're using the wrong data.