Fix weather particle physics.

The trait documentation specified that the speed
and offset values are px/tick, but they have actually
always been treated as px/render.

Fix the update logic and rescale the map definitions
to account for the fixed behaviour.

mods/ra/maps/a-nuclear-winter/rules.yaml

@@ -1,16 +1,10 @@
 World:
 	WeatherOverlay:
 		ChangingWindLevel: true
-		WindLevels: -5, -3, -2, 0, 2, 3, 5, 6
-		WindTick: 150, 550
 		InstantWindChanges: false
 		UseSquares: true
 		ParticleSize: 2, 3
 		ScatterDirection: -1, 1
-		Gravity: 1.00, 2.00
-		SwingOffset: 1.0, 1.5
-		SwingSpeed: 0.001, 0.025
-		SwingAmplitude: 1.0, 1.5
 		ParticleColors: ECECEC, E4E4E4, D0D0D0, BCBCBC
 		LineTailAlphaValue: 0
 	GlobalLightingPaletteEffect:

mods/ra/maps/fort-lonestar/rules.yaml

@@ -10,7 +10,7 @@ World:
 		WindTick: 150, 550
 		UseSquares: false
 		ScatterDirection: 0, 0
-		Gravity: 8.00, 12.00
+		Gravity: 15, 25
 		SwingOffset: 0, 0
 		SwingSpeed: 0, 0
 		SwingAmplitude: 0, 0

mods/ra/maps/shattered-mountain/rules.yaml

@@ -1,17 +1,10 @@
 World:
 	WeatherOverlay:
 		ChangingWindLevel: true
-		WindLevels: -5, -3, -2, 0, 2, 3, 5, 6
-		WindTick: 150, 550
 		InstantWindChanges: false
 		UseSquares: true
 		ParticleSize: 2, 3
 		ParticleDensityFactor: 8
-		ScatterDirection: -1, 1
-		Gravity: 1.00, 2.00
-		SwingOffset: 1.0, 1.5
-		SwingSpeed: 0.001, 0.025
-		SwingAmplitude: 1.0, 1.5
 		ParticleColors: ECECEC, E4E4E4, D0D0D0, BCBCBC
 		LineTailAlphaValue: 0
 	GlobalLightingPaletteEffect:

mods/ra/maps/snow-town/rules.yaml

@@ -1,16 +1,8 @@
 World:
 	WeatherOverlay:
 		ChangingWindLevel: true
-		WindLevels: -5, -3, -2, 0, 2, 3, 5
-		WindTick: 150, 550
 		InstantWindChanges: false
 		UseSquares: true
-		ParticleSize: 1, 3
-		ScatterDirection: -1, 1
-		Gravity: 1.00, 2.00
-		SwingOffset: 1.0, 1.5
-		SwingSpeed: 0.001, 0.025
-		SwingAmplitude: 1.0, 1.5
 		ParticleColors: ECECEC, E4E4E4, D0D0D0, BCBCBC
 		LineTailAlphaValue: 0
 	GlobalLightingPaletteEffect: