Blank column headers in template

I am generating unique ids from some other fields being imported (via csv/spreadsheet upload), which means this unique field isn't meant to be provided by the user directly. So it has a blank label in it's source. However, when users download the template file, they get a blank column (no header) as the first column. This is because the FeedsCSVParser->getTemplate() merges unique fields and sources together, with the uniques as the first argument of array_merge()

foreach (array_merge($uniques, $sources) as $col) {

In other words, the blank column is first regardless of the order it is defined in the processor. Understandably, this may be a bit of a specific use case, and doesn't really cause any serious bugs per se, but having an empty column in the beginning of the document looks weird to external users.

I propose adding a check on the value of $col before appending to the $columns array in FeedsCSVParser->getTemplate() ,

      if (!empty(trim($col))) {
        $columns[] = $col;
      }

Patch coming. Take it or leave it. I just have a policy of filing an issue and patch if I need to modify a contrib module.