GPS Navigation

[s-hliao]

Pull coordinates from our competition area, and navigate sequentially through those coordinates.

This issue comprises of a node/set of nodes that are able to add a set of GPS waypoints to a list (based on a message recieved), have the robot navigate to those GPS waypoints sequentially (and end at those waypoints within a +/- 1.5 m error), and return when the robot has completed the path.

After path completion, rover should stop listen for new waypoints to add to the list and a "continue" command, such that it begins executing the next set of waypoints.

Sets of waypoints will be published on a topic in order to be transferred to the robot. Message could either be generated as a json, or sent directly from the web interface (see #80).

Since legs 1 and 2 of the autonomous portion are largely flat and do not require significant obstacle avoidance, a simple movement algorithm such as a PID or LQR to get a robot from one position to another should suffice.