Export Unicode data to csv: UnicodeEncodeError

[aprilmay]

Unicode data in fields break the csv export with an UnicodeEncodeError exception (mixins.py line 92, in build_csv_response).

Validated a quick fix, that would require using the unicodecsv drop-in replacement for the standard csv module.

In mixins.py, just replace:
import csv
by
import unicodecsv as csv

[AMongeMoreno]

I found another solution for this bug, it just require using the smart_str function provided by django in lines 98 and 148.
It is still open, btw