tweaks to force management
added asyc task to make scans added to the graphics view come in staggered, to allow the relations room to develop.  Added handling to avoid concurrency issues with lists in group node and moveable actor.
Trying to work out how to build connections between new scans and points and existing actors as scans and their associated connections are introduced one by one.  Then again, it's like half one in the morning, who am I kidding...