Include shape support for video and pointalism + some missing bits

The video and pointalism pipelines now take into account
entity geometry. Also includes some missing changes that
probably got lost during the merge with wip/rib/master-next
pointalism: Add shape toggle support for video/pointalism

Toggling the shaped property of the material used to
cause a crash. This was fixed by adding pipeline dirty
logic.
Fix the position used for dragging entities

There were two problems which broke the position when dragging an
entity. Firstly is was using the wrong camera to work out the offset
vectors. It was taking the camera from the event which triggered the
drag. Presumably this would previously end up being the view camera
but at some point it changed to the global editor camera. This patch
just forces it to be the view camera.

Secondly if you begin the drag by selecting an entity then the
property inspector will start being displayed which will cause the
camera view to resize. The offset vectors were only being calculated
once with the original size so they would no longer be correct after
the inspector is displayed. This patch makes it maintain a pointer to
the translate grab closure from the RigCameraView and it will make
sure to update the offset vectors during allocate. This is a bit hacky
because it needs to flush the viewport on the view camera and update
the view transforms in order to get the right calculation.