Default activity completion - Can not add jQuery plugins after starting page output!

[opitz]

There are issues with the Course Completion (unrelated to #701).

If course completion is on and you try to view "Default activity completion" for a course the following error can be seen:

Can not add jQuery plugins after starting page output!
The error appears for these lines:
line 135 of /mod/turnitintooltwo/mod_form.php: call to page_requirements_manager->jquery()
line 136 of /mod/turnitintooltwo/mod_form.php: call to page_requirements_manager->jquery()
line 137 of /mod/turnitintooltwo/mod_form.php: call to page_requirements_manager->jquery()
line 138 of /mod/turnitintooltwo/mod_form.php: call to page_requirements_manager->jquery()
line 139 of /mod/turnitintooltwo/mod_form.php: call to page_requirements_manager->jquery()

Furthermore it shows:
No formslib form description file found for this activity.
This breaks the page and needs to be fixed.