story type is case-sensitive for imported files

I recently imported a CSV file where all of the story types were capitalized (so I had "Feature" instead of "feature"). I also had labels, which were valid. After clicking "import" I got an error stating that I couldn't insert null into story_id on the labelling table.

What appears to have happened is that it choked on the story type, but for some reason kept going and tried to insert the labels, but the story wasn't created, so it failed.

I think 2 things should happen: 1) story type should be case insensitive - I should be able to add "Feature" or "Chore" and 2) when the feature type is incorrect, the error should be correctly reported