UK: _notes is stored as a dict export as a string, close #384
UK: use sorted records for test
Merge pull request #388 from onaio/384-xls-export-error2

fix  TypeError: sequence item 0: expected string, dict found
UK: delete temp file after export
UK: remove attachment.full_filepath, prevent creation of unnecessary temp files
UK: pep8
UK: compare sorted values
UK: use try .. finally to close temp_file
UK: code refactor: ensure file is closed properly
PLD: remove unused streaminghttpresponse
PLD: use helper to build HttpResponse
PLD: close zips if finally if not none