Support a maximum building range (Fixes #2156).

This also implements support for a per-provider
cooldown between placing structures, allowing mods
with multiple structure queues to rate-limit
placement around a single provider.

An initial delay parameter is included to
support units that deploy into a base provider and
require an initial setup time (e.g. the Surveyor
unit from C&C TW).

The range and time restrictions are not applied to
walls as a balance choice.

OpenRA.Mods.RA/Render/RenderBuilding.cs

@@ -19,7 +19,7 @@ using OpenRA.Mods.RA.Activities;
 
 namespace OpenRA.Mods.RA.Render
 {
-	public class RenderBuildingInfo : RenderSimpleInfo
+	public class RenderBuildingInfo : RenderSimpleInfo, Requires<BuildingInfo>, IPlaceBuildingDecoration
 	{
 		public readonly bool HasMakeAnimation = true;
 		public readonly float2 Origin = float2.Zero;
@@ -30,6 +30,15 @@ namespace OpenRA.Mods.RA.Render
 			return base.RenderPreview(building, pr)
 				.Select(a => a.WithPos(a.Pos + building.Traits.Get<RenderBuildingInfo>().Origin));
 		}
+
+		public void Render(WorldRenderer wr, World w, ActorInfo ai, PPos centerLocation)
+		{
+			if (!ai.Traits.Get<BuildingInfo>().RequiresBaseProvider)
+				return;
+
+			foreach (var a in w.ActorsWithTrait<BaseProvider>())
+				a.Trait.RenderBeforeWorld(wr, a.Actor);
+		}
 	}
 
 	public class RenderBuilding : RenderSimple, INotifyDamageStateChanged, IRenderModifier