Revert new PID stuff and move it to a separate branch for now.

src/utils.c

@@ -14,16 +14,6 @@ int constrain(int amt, int low, int high)
         return amt;
 }
 
-float constrainf(float amt, float low, float high)
-{
-    if (amt < low)
-        return low;
-    else if (amt > high)
-        return high;
-    else
-        return amt;
-}
-
 void initBoardAlignment(void)
 {
     float roll, pitch, yaw;