Change the way heading (other angles) is defined

[haakov]

Right now heading (and global wind) is defined such that:

• 0 deg - East
• 90 deg - North
  (like the unit circle)

the measured wind is defined similarly, with 0 degrees being wind toward starboard, 90 degrees being tailwind. The angle describes where the wind is blowing towards, not where it is coming from.

I haven't encountered this convention before, and I think it would be wise to define all angles clockwise, with 0 pointing North, which would be equal to how a compass is defined:

Also, the wind angle is usually defined as the direction it's coming from, not where it's going. I. e. 0 degrees is headwind. I think we should do these changes in order to make the code easier to work with and improve maintainability.

@tylerlum thoughts?