sixDoFRigidBodyMotion → sixDoFSolvers Relation

File in src/sixDoFRigidBodyMotion/sixDoFRigidBodyMotion	Includes file in src/sixDoFRigidBodyMotion/sixDoFSolvers
sixDoFRigidBodyMotion.C	sixDoFSolver / sixDoFSolver.H
sixDoFRigidBodyMotionIO.C	sixDoFSolver / sixDoFSolver.H