Implement cnc harv/proc dock sequence and kill unnecessary duplication. Bad things happen if sequence is interrupted by another order (eg invisible harv).

Still todo: Make sequence non-interruptible; engineer steals harv docked with proc; the "right thing" if proc is sold/destroyed with harv docked.

OpenRA.Mods.RA/Activities/Drag.cs

@@ -0,0 +1,55 @@
+#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 OpenRA.Traits;
+using OpenRA.Traits.Activities;
+
+namespace OpenRA.Mods.RA.Activities
+{
+	public class Drag : IActivity
+	{
+		public IActivity NextActivity { get; set; }
+
+		float2 endLocation;
+		float2 startLocation;
+		int length;
+
+		public Drag(float2 start, float2 end, int length)
+		{
+			startLocation = start;
+			endLocation = end;
+			this.length = length;
+		}
+		
+		int ticks = 0;
+		public IActivity Tick( Actor self )
+		{
+			self.CenterLocation = float2.Lerp(startLocation, endLocation, (float)ticks/(length-1));
+			
+			if (++ticks >= length)
+				return NextActivity;
+			
+			return this;
+		}
+
+		public void Cancel(Actor self) {	}
+	}
+}