Make setToIKSolverFrame accessible again (moveit#2580)

This is public API because the solver's getPositionIK requires input poses
in the frame and the relevant transform is otherwise inaccessible.

Partially reverts moveit#2461.

moveit_core/robot_state/include/moveit/robot_state/robot_state.h

@@ -1831,18 +1831,13 @@ as the new values that correspond to the group */
 
   std::string getStateTreeString(const std::string& prefix = "") const;
 
-private:
-  void allocMemory();
-  void initTransforms();
-  void copyFrom(const RobotState& other);
-
   /**
    * \brief Transform pose from the robot model's base frame to the reference frame of the IK solver
    * @param pose - the input to change
    * @param solver - a kin solver whose base frame is important to us
    * @return true if no error
    */
-  inline bool setToIKSolverFrame(Eigen::Isometry3d& pose, const kinematics::KinematicsBaseConstPtr& solver);
+  bool setToIKSolverFrame(Eigen::Isometry3d& pose, const kinematics::KinematicsBaseConstPtr& solver);
 
   /**
    * \brief Transform pose from the robot model's base frame to the reference frame of the IK solver
@@ -1852,6 +1847,11 @@ as the new values that correspond to the group */
    */
   bool setToIKSolverFrame(Eigen::Isometry3d& pose, const std::string& ik_frame);
 
+private:
+  void allocMemory();
+  void initTransforms();
+  void copyFrom(const RobotState& other);
+
   void markDirtyJointTransforms(const JointModel* joint)
   {
     dirty_joint_transforms_[joint->getJointIndex()] = 1;