added first summit_xl_multi.launch
summit_xl_gazebo. Fixed sintaxis error in summit_xl_multi.launch
Updated launch files and gazebo files
Fixed more files
summit_xl.urdf.xacro. Fixed wheel positions to fix movement
Fixed omni movement
Added tf_prefix to urdf links
Now it uses a tf_prefix for the odom->base_footprint transform
Delete debugging displays
Allows multiple simulations of summit xl (not omni wheels yet)
Minor fix
Fixed ptz controller error
Added missing hokuyo hq model
Merge pull request #1 from JorgeArino/master

Allow multiple simulations