compile gazebo plugins in hydro: no error occurs in hydro.
added SetVelPlugin/VelCommand interface in gazebo-plugin-utils.l
add full path for world file setting in gazebo_simplebox.launch
added comments to gazebo-plugin-utils.l
defmethod to hrp2jsknt-interface only when the class was defined.
generate hand urdf model with plugin for setting and getting velocity and force in the optinal_setting scripts.
revert 9fc1c794e86ca23d105605092a3a6c2bdb76a59a
comment out the usage output in gazebo-plugin-utils.l
revert adding light to the world.
do not add urdf robot_models directories to ROS_PACKAGE_PATH.
Merge pull request #14 from mmurooka/master

compile gazebo plugins in hydro, do not add robot urdf directories to ROS_PACKAGE_PATH, and etc