Added gaussian noise to depth camera
Fix the robot namespace for URDF
Added the robot namespace to the tf prefix.

The tf_prefix param is published under the robot namespace and not the
robotnamespace/camera node which makes it non-local we have to use the
robot namespace to get it otherwise it is empty.
Merge pull request #6 from fmder/tf-prefix

Added the robot namespace to the tf prefix.
Merge branch 'robot-namespace' into groovy-devel
Merge github.com:osrf/gazebo_ros_pkgs into groovy-devel