Checkin of challenge code from old repo (but without excessive history)

CMakeLists.txt

README.md

hosts.txt

launch/bag/challenge1_bag.launch

launch/challenge1.launch

launch/challenge1_collect_lab_data.launch

launch/challenge1_general.launch

launch/challenge1_run_sim.launch

launch/real/challenge1_build_map_real.launch

launch/real/challenge1_real.launch

launch/sim/challenge1_build_map_sim.launch

launch/sim/challenge1_sim.launch

launch/turtlebot3_house_headless.launch

package.xml

rviz/turtlebot3_gazebo_model.rviz

scripts/absolute_trajectory_error.py

scripts/challenge1_correct_gps.py

scripts/challenge1_correct_imu.py

scripts/challenge1_correct_odom.py

scripts/challenge1_route.py