OO-3404: allow to copy alien assessment item, show an error if the user try to copy an unreadable assessment item

OO-3403: mordenize the tiny helper to send a command to TinyMCE, set a default size for the player for audio file, better resize of the preview player

OO-3398: add special rendering form item for disabled mode in question pool to show videos and images in feedbacks

OO-3398: add special rendering form item for disabled mode in question pool to show videos and images

OO-3339: move previous / next buttons to a separate controller to catch dirty form events, add some tricks to set the form as dirty for the override callout...

OO-3396: make the QTI 1.2 results export resilient to missing result XML of a particular participant