sixDoFRigidBody: adding constraints.

src/postProcessing/functionObjects/forces/Make/files

...lds/derived/sixDoFRigidBodyMotion/sixDoFRigidBodyMotion.C

...lds/derived/sixDoFRigidBodyMotion/sixDoFRigidBodyMotion.H

...n/sixDoFRigidBodyMotionConstraint/fixedPoint/fixedPoint.C

...n/sixDoFRigidBodyMotionConstraint/fixedPoint/fixedPoint.H

...BodyMotionConstraint/newSixDoFRigidBodyMotionConstraint.C

...gidBodyMotionConstraint/sixDoFRigidBodyMotionConstraint.C

...gidBodyMotionConstraint/sixDoFRigidBodyMotionConstraint.H

...ds/derived/sixDoFRigidBodyMotion/sixDoFRigidBodyMotionI.H

...ixDoFRigidBodyMotionRestraint/linearSpring/linearSpring.C

...ixDoFRigidBodyMotionRestraint/linearSpring/linearSpring.H

...idBodyMotionRestraint/newSixDoFRigidBodyMotionRestraint.C

...RigidBodyMotionRestraint/sixDoFRigidBodyMotionRestraint.C

...RigidBodyMotionRestraint/sixDoFRigidBodyMotionRestraint.H