improved way of importing/publishing HITs.

- CSV file for row of data for creating HITs is now expected to
  be:
  - UTF-8
  - excel dialect
  - with a header row
- Added `unicodecsv` package dependency.

Closes #5.
simply de-indent a bunch of lines.
store HIT field names and values as JSON lists in the Hit model's text field
pep8 improvements