Support for unicode csv output.

All strings in csv output are utf-8 encoded.  Added unit tests to verify
correct operation with unicode data input.

Use of Django test runner requires that a models.py be present, so empty
models file added.
Ensure unpaginated table is output to csv.

When a paginated table is provided to TableReport, output the full row
set rather than paginated data.
Unit test for xls generation containing unicode chars.