Added the PositionJointSaturationInterface and VelocitySoftLimitsInterface
classes. There are now saturation and soft limit classes for effort-controlled,
position-controlled, and velocity-controlled joints.
Updated the interface list.
Merge pull request #124 from jim-rothrock/hydro-devel

Added the PositionJointSaturationInterface and VelocityJointSoftLimitsInterface classes.