Sample consensus doesn't give back the correct model

[vadixidav]

When solving the two-view pose using the EightPoint algorithm in sample consensus, the incorrect model is returned. The cheirality check that occurred in EssentialMatrix::solve_pose was removed when EightPoint was changed to return 4 separate poses, which are only checked based on cosine distance, not cheirality. Cheirality must be checked in the code for the CameraToCamera transformation model residual for it to work correctly.