Delete Shapes Logic Changed

Delete tool was a working component that have it's really strong point but also some shortcomings like: some chain of shapes do make some kind of shapes to dangle (like if you delete a rectangle and attached to it was a dimension, this dimension was simply inaccessible to delete and remain as artifact in scene). In the past the deleting was done like this: hide the shape, and if the shape was unreachable and all it's shapes that are unreachable, they were removed.
As right now it explicitly lookup of it's dependencies and it's referees and makes the deletion more consistent and hopefully glitch free.