Limit sim rate to 1x real time

[wfvining]

We have discussed limiting the sim rate to 1x real time for the virtual phase of the competition due to reproducibility issues that arise when running in excess of real time. With 6 robots it is unlikely our machines will run faster than 0.6 real time, but we should limit just to be safe.

[Carter90]

From my email from the tech session

Sim speed is not limited to real time because of physics stepping problems caused by Line 36 in src/gazebo_plugins/src/SetupWorld.cpp physicsMsg.set_real_time_update_rate(0) This overwrites the physics in the world to go as fast as the system will allow and can cause inconsistent sim runs if the machine runs in excess of real time with a fluctuating real time factor.