Change animations to use the proper SequenceProvider

Remove references to the global "Game" and use the SequenceProvider
of the current world/map.

OpenRA.Mods.RA/Effects/NukeLaunch.cs

@@ -45,7 +45,7 @@ namespace OpenRA.Mods.RA.Effects
 			descendSource = targetPos + offset;
 			descendTarget = targetPos;
 
-			anim = new Animation(weapon);
+			anim = new Animation(firedBy.World, weapon);
 			anim.PlayRepeating("up");
 
 			pos = launchPos;