Warning if the boat detects that the direction of travel is off from expected

[shawnhanna]

This might be more of a controls issue, but when the robot isn't following the line very well, it might be nice to show a warning that it isn't running the route as well as expected

• maybe shown if the amount off of the line is > 10m
• or if the angle of robot vs gps velocity shows it is going are off by a significant amount