stage_ros breaks REP 105

[MichaelKorn]

Hello
In http://www.ros.org/reps/rep-0105.html you can find: "The base_link can be attached to the base in any arbitrary position or orientation".
In https://github.com/ros-simulation/stage_ros/blob/master/src/stageros.cpp#L490 stage_ros forces the base_link to be on the ground. Because of this I suppose my problem turtlebot/turtlebot_simulator#53 is the fault of the stage_ros.

Regards,
Michael