Generate weather conditions at turn start.

Weather and exact time of day information is helpful during mission
planning, so generate it at the start of the turn rather than at
takeoff time.

Another advantage aside from planning is that we can now use the wind
information to set carrier headings and takeoff runways appropriately.

game/operation/operation.py

@@ -21,7 +21,7 @@ from gen.airsupportgen import AirSupport, AirSupportConflictGenerator
 from gen.armor import GroundConflictGenerator, JtacInfo
 from gen.beacons import load_beacons_for_terrain
 from gen.briefinggen import BriefingGenerator
-from gen.environmentgen import EnviromentGenerator
+from gen.environmentgen import EnvironmentGenerator
 from gen.forcedoptionsgen import ForcedOptionsGenerator
 from gen.groundobjectsgen import GroundObjectsGenerator
 from gen.kneeboard import KneeboardGenerator
@@ -45,7 +45,6 @@ class Operation:
     triggersgen = None  # type: TriggersGenerator
     airsupportgen = None  # type: AirSupportConflictGenerator
     visualgen = None  # type: VisualGenerator
-    envgen = None  # type: EnviromentGenerator
     groundobjectgen = None  # type: GroundObjectsGenerator
     briefinggen = None  # type: BriefingGenerator
     forcedoptionsgen = None  # type: ForcedOptionsGenerator
@@ -162,13 +161,9 @@ class Operation:
         for frequency in unique_map_frequencies:
             radio_registry.reserve(frequency)
 
-        # Generate meteo
-        envgen = EnviromentGenerator(self.current_mission, self.conflict,
-                                     self.game)
-        if self.environment_settings is None:
-            self.environment_settings = envgen.generate()
-        else:
-            envgen.load(self.environment_settings)
+        # Set mission time and weather conditions.
+        EnvironmentGenerator(self.current_mission,
+                             self.game.conditions).generate()
 
         # Generate ground object first