Units automatically path around known hazards (eg static base defenses). Test using SAM and TRAN.

Todo: Ignore hazards when force-moving; Apply only to known enemy hazards; Implement more hazard classes

Also add a few files I forgot from previous patches

OpenRA.Game/Traits/Hazardous.cs

@@ -0,0 +1,52 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007,2009,2010 Chris Forbes, Robert Pepperell, Matthew Bowra-Dean, Paul Chote, Alli Witheford.
+ * This file is part of OpenRA.
+ * 
+ *  OpenRA is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ * 
+ *  OpenRA is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ * 
+ *  You should have received a copy of the GNU General Public License
+ *  along with OpenRA.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#endregion
+
+using System.Linq;
+using System.Collections.Generic;
+
+namespace OpenRA.Traits
+{
+	class AntiAirInfo : ITraitInfo
+	{
+		public readonly float Badness = 1000f;
+		public object Create( ActorInitializer init ) { return new AntiAir( init.self ); }
+	}
+	
+	class AntiAir : IProvideHazard
+	{
+		public AntiAir(Actor self)
+		{
+			self.World.WorldActor.traits.Get<HazardLayer>().Add( self, this );
+		}
+		
+		public IEnumerable<HazardLayer.Hazard> HazardCells(Actor self)
+		{
+			var info = self.Info.Traits.Get<AntiAirInfo>();
+			return self.World.FindTilesInCircle(self.Location, (int)self.GetPrimaryWeapon().Range).Select(
+			      	t => new HazardLayer.Hazard(){location = t, type = "antiair", intensity = info.Badness});
+		}
+	}
+	
+	class AvoidsAAInfo : TraitInfo<AvoidsAA> {}
+	class AvoidsAA : IAvoidHazard
+	{
+		public string Type { get { return "antiair"; } }
+	}
+}