Bulk Upload: Removed redundant tests and added tests to check one can't get
beyond the display_csv_file page without a file that passes validation.
Bulk Upload: In the confirm_data and insert_data actions, redirect to the
choose_global_data_values if the form on that page was never submitted.
Bulk Upload:

Amendment to last commit: Use the existence of session[:rounding] as the
indicator of whether the 'choose_global_data_values' form has ever been
submitted, since session[:global_values] may legitimately be nil if all required
data was included in the upload file.

Added two new tests to check that needed global information has been submitted
and that the user is redirected back to the form if not.

Tightened up a test for successful data insertion.