Moving extra fixed link out of ur10.urdf.xacro and into ur10_robot.urdf.xacro

Also removing virtual joint from MoveIt! configuration.
Removed cube.dae from meshes
Removed all *.stl files from UR10 meshes.
Removed ur10_joint_limited.urdf.xacro and accomplished this with

xacro arguments. Replaced all tabs with spaces. Updated the UR10 urdf files.
Fixing use_gui parameter in joint_state_publisher node in launch file.
Merge branch 'ur10_urdf_update' into ur10_moveit

Conflicts:
	ur_description/urdf/ur10.urdf.xacro
	ur_description/urdf/ur10_joint_limited.urdf.xacro