Adds a set of options to the essay question type which implement
the following new features:
-Adds an input format which accepts only file uploads, and no
inline text.
-Adds an option to make the inline text response optional when
attachments are enabled, so students can choose to upload
an essay file.
-Adds an option to make attachments required, so essays without
attachments will be marked incomplete.
1/ type/match/tests/walkthrough_test.php - tests are failing randomly, looks like some weird randomisation is going on there - see TODOs
2/ type/multianswer/tests/upgradelibnewqe_test.php contains invalid expected value - see TODO
Tim Hunt