Create "integration test" environment in Gazebo so that the CNN can be integration tested as well

[oswinso]

Currently, the only way to "integration test" the CNN is by testing on Jessii. However, it would be nice to get a sanity check by having a "integration test" environment and corresponding .launch file so that we can at least check that the our CNN code doesn't crash.

AC: A integration_simulation.launch file that launches a (maybe small) version of autonav where the lines are white and launches the CNN node instead of sim_color_detector.