MDL-12418 "Item Analysis shows duplicate responses for Multiple Choice questions...

MDL-12418 "Item Analysis shows duplicate responses for Multiple Choice questions with LaTeX in answers" This problem was caused by the formatting of questions in get_actual_responses. Now formatting is done in response_summary rather than get_actual_response which returns an array of unformatted strings.

Have fixed the formatting in responses report and in statistics report to use the correct formatting for the question type.

Created new functions format_responses and format_response. format_responses works on an array and normally just walks through the array calling format_response.