Fixed bug - tool content id was not being updated when a tool activity was updated. The code that handles the special fields for tool activities, optional activities, etc wasn't being called.
The getActivityByUUID now gets the real activity, rather than the hibernate CGLIB version, to avoid classcast errors when updating an activity in authoring.
The rule to work out whether to pre-initialise the tool session was wrong. Was initialising for grouped activities, we want to initialise the non-grouped activities.