Convert to new unit APIs, remove old APIs.

There are probably plenty of raw ints around that never used the old
conversion APIs, but we'll just need to fix those when we see them.

Fixes https://github.com/Khopa/dcs_liberation/issues/558

gen/kneeboard.py

@@ -33,8 +33,7 @@ from dcs.mission import Mission
 from dcs.unittype import FlyingType
 from tabulate import tabulate
 
-from game.utils import meter_to_nm
-from . import units
+from game.utils import meters
 from .aircraft import AIRCRAFT_DATA, FlightData
 from .airsupportgen import AwacsInfo, TankerInfo
 from .briefinggen import CommInfo, JtacInfo, MissionInfoGenerator
@@ -170,10 +169,10 @@ class FlightPlanBuilder:
         if self.last_waypoint is None:
             return "-"
 
-        distance = meter_to_nm(self.last_waypoint.position.distance_to_point(
+        distance = meters(self.last_waypoint.position.distance_to_point(
             waypoint.position
         ))
-        return f"{distance} NM"
+        return f"{distance.nautical_miles:.1f} NM"
 
     def _ground_speed(self, waypoint: FlightWaypoint) -> str:
         if self.last_waypoint is None:
@@ -189,19 +188,11 @@ class FlightPlanBuilder:
         else:
             return "-"
 
-        distance = meter_to_nm(self.last_waypoint.position.distance_to_point(
+        distance = meters(self.last_waypoint.position.distance_to_point(
             waypoint.position
         ))
         duration = (waypoint.tot - last_time).total_seconds() / 3600
-        try:
-            return f"{int(distance / duration)} kt"
-        except ZeroDivisionError:
-            # TODO: Improve resolution of unit conversions.
-            # When waypoints are very close to each other they can end up with
-            # identical TOTs because our unit conversion functions truncate to
-            # int. When waypoints have the same TOT the duration will be zero.
-            # https://github.com/Khopa/dcs_liberation/issues/557
-            return "-"
+        return f"{int(distance.nautical_miles / duration)} kt"
 
     def build(self) -> List[List[str]]:
         return self.rows