Merge pull request #4599 from RosettaCommons/roccomoretti/void_sphere_mutex
Foldit: Fix issue with VoidSphere deadlock.
There's a chance that the void calculation can deadlock, as the VoidFilter and the Void calculation thread were grabbing the data_mutex_ and the GUI mutex in opposite orders. By delaying the creation of the VoidSpheres, we can avoid the deadlock.