Quoted fields at end of row are silently dropped

[nathankleyn]

Many thanks for such a great piece of software, we chose to use your library for some big-data processing because we found it had vastly better performance than anything else! Huge thanks!

We ran into a slightly obscure bug parsing some huge CSVs: a field that appears at the end of a row that is quoted but empty gets silently dropped. Here's an example:

"foo",""

If you run this test you'll see it fails:

public void handlesEmptyQuotedFieldsAtEndOfRow() throws IOException {
  assertEquals(readCsvRow("foo,\"\"").getField(1), "");
}

We ran into this because we receive CSVs that have all fields quoted, even empty ones, and couldn't work out why accessing the final field would sometimes lead to an ArrayIndexOutOfBoundsException.

I've had an attempt at a fix for this which I'll raise a PR for momentarily, and I've done my best to try to stick to the performance sensitive methods you are using, but eager for feedback if I've done anything not to your liking!

Please let me know if we can help in any other way!

[nathankleyn]

Have raised PR with (hopefully) an okay fix for this in #20. 🤞