Create LIDAR processing node

[mbr4477]

Converts LIDAR data to structured obstacle messages.

[mbr4477]

I believe this has been completed by @irowebbn, but I'm not sure if it has been merged back into the master/dev branch. Leaving open until that can be confirmed.

[ruffner]

Any update on this?

[irowebbn]

@ruffner See ca93ee2

The obstacle classification works, and you can verify that by running the plotTest function and see a test with some of the sample data from https://github.com/UKyKORA/IGV/blob/master/sample_data/courtyard.txt

I'm remote for the semester, so I haven't been able to test this with real hardware or data, so that's why the ROS stuff at the top is commented out. I haven't tried it yet. The node assumes a couple of ROS topics that don't currently exist, including LIDAR point cloud, and range to target. I also haven't tested any of the actual avoidance logic (the adjust_heading methods in each of the obstacle classes). That would be the next step to test.

[irowebbn]

I also still need to add the 3x3 filter