Fix the rotation of the 3D scene to the center of the head

[vhosouza]

When navigating and markers are created far from the head, the center of camera rotation in the 3D science is dynamically adjusted to the "average coordinate" of all surfaces in the scene. Thus, even a single marker created far from the head will cause difficulties in rotating the scene.

We should have a fixed origin for camera rotation that is in the center of the head.