Updating SCORM without losing attempts

What's new

• update_scorm — replaces a SCORM's package without losing its activity id, its attempts or its tracking. Until now the only way to fix published content was to delete the activity and recreate it, which broke direct links and lost student attempts. The package is optional: omit it to change only the settings.
• Full SCORM settings on create and update — grading method, maximum grade, attempts and attempt locking, display and navigation, and the open/close dates. Every field is optional; what you omit keeps its previous behaviour.
• update_section — updates a course section's name, summary and visibility. The section summary was the one text surface in a course with no web service able to write it.

Fixed

• create_scorm hardcoded the grading method to "highest grade of any SCO", so a SCORM created this way graded differently from one created through the settings form. It's now overridable, and stays the default when omitted.