Implement joint_limit_controller

[mathias-luedtke]

• controller that chains other controllers
• soft limit according to http://wiki.ros.org/pr2_controller_manager/safety_limits
• enforce hard position limits for all interfaces
• open loop maximum vel, acc, eff filters

@fmessmer FYI

[fmessmer]

For the moment done in ros_canopen (see https://github.com/ros-industrial/ros_canopen/tree/limited_joint_handle)

[fmessmer]

A summary about current approaches and insights is given in ipa320/cob_gazebo_plugins#14 (comment)

@ipa-mdl
Let's continue the discussion about the "joint_limit_controller" (e.g. for limiting "jumps" in the command) here