Make acceleration calculation in turnToHeading float, not int, and get rid of rounding safety code. Also change sign so that sccel is negative when we are moving too fast.
goToGoal and turnToHeading are relative function only now, there is no global odometry space. Odometer::setCurrentPosition has been made private again.

Also, decision to go backwards or forwards in goToGoal is based on our current heading, are we facing towards the goal or away.
Now have "standard" turn and move functions that are relative to the robot space, while goToGoal is in the world frame only. Odometer has a transformation function to support this. followWall has introduced PID behavior and linear velocity control that persists through repeated calls to that function.