Sonar Proximity Simulation

[ericjohnson97]

Merge adds:

• Lake Travis world with trees and house
• updates drone with sonar to use my custom plugin that is contained here https://github.com/Intelligent-Quads/gazebo_ros_pkgs
• • Custom plugin changes range plugin to publish nan when > range finder max_range
• updates to apm.launch to accept config_yaml as argument
• adds 4proximity.yaml - file that accepts rangefinder proximity data via mavlink

[ericjohnson97]

• also improves hit boxes on iris base