Implemented: Stances

Added: Basic stances (Aggressive, Guard (Hold Ground), Hold Fire, None (dummy), Return Fire)
Added: WorldCommandWidget (to be able to set said stances)
Added: WorldCommandWidget to ra (cnc will follow, later on)
Changed: Added support to AttackBase for firing with movement disabled + utility method ScanForTarget (used by stances)
Added: AssignUnitStance (attach this to unit-producing actors, together with what stances can be picked as 'default')

OpenRA.Mods.RA/UnitStances/UnitStanceReturnFire.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Drawing;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.RA
+{
+	public class UnitStanceReturnFireInfo : UnitStanceInfo
+	{
+		public override object Create(ActorInitializer init) { return new UnitStanceReturnFire(init.self, this); }
+	}
+
+	/// <summary>
+	/// Return Fire
+	/// 
+	/// Will fire only when fired upon
+	/// </summary>
+	public class UnitStanceReturnFire : UnitStance, INotifyDamage, ISelectionColorModifier
+	{
+		public UnitStanceReturnFire(Actor self, UnitStanceReturnFireInfo info)
+		{
+			Info = info;
+			Active = (self.World.LocalPlayer == self.Owner || (self.Owner.IsBot && Game.IsHost)) ? Info.Default : false;
+		}
+
+		public void Damaged(Actor self, AttackInfo e)
+		{
+			if (!Active) return;
+			if (!self.HasTrait<AttackBase>()) return;
+
+			ReturnFire(self, e, false); // only triggers when standing still
+		}
+
+		public Color GetSelectionColorModifier(Actor self, Color defaultColor)
+		{
+			return Active ? Color.Orange : defaultColor;
+		}
+	}
+}