Implement non-linear position stabilization for the generic constraint.

src/dynamics/solver/joint_constraint/joint_position_constraint.rs

@@ -242,20 +242,4 @@ impl AnyJointPositionConstraint {
             AnyJointPositionConstraint::Empty => unreachable!(),
         }
     }
-
-    pub fn solve2(
-        &self,
-        params: &IntegrationParameters,
-        positions: &mut [Isometry<Real>],
-        dpos: &mut [DeltaVel<Real>],
-    ) {
-        match self {
-            AnyJointPositionConstraint::GenericJoint(c) => c.solve2(params, positions, dpos),
-            AnyJointPositionConstraint::GenericGroundConstraint(c) => {
-                c.solve2(params, positions, dpos)
-            }
-            _ => {}
-            AnyJointPositionConstraint::Empty => unreachable!(),
-        }
-    }
 }