Fix Neutral crushing checks.

OpenRA.Game/Primitives/LongBitSet.cs

@@ -18,6 +18,7 @@ namespace OpenRA.Primitives
 	static class LongBitSetAllocator<T> where T : class
 	{
 		static readonly Cache<string, long> Bits = new Cache<string, long>(Allocate);
+		static long allBits = 1;
 		static long nextBits = 1;
 
 		static long Allocate(string value)
@@ -25,6 +26,7 @@ namespace OpenRA.Primitives
 			lock (Bits)
 			{
 				var bits = nextBits;
+				allBits |= bits;
 				nextBits <<= 1;
 
 				if (nextBits == 0)
@@ -85,6 +87,8 @@ namespace OpenRA.Primitives
 				nextBits = 1;
 			}
 		}
+
+		public static long Mask { get { return allBits; } }
 	}
 
 	// Opitmized BitSet to be used only when guaranteed to be no more than 64 values.
@@ -114,6 +118,7 @@ namespace OpenRA.Primitives
 
 		public static bool operator ==(LongBitSet<T> me, LongBitSet<T> other) { return me.bits == other.bits; }
 		public static bool operator !=(LongBitSet<T> me, LongBitSet<T> other) { return !(me == other); }
+		public static LongBitSet<T> operator ~(LongBitSet<T> me) { return new LongBitSet<T>(me.bits ^ LongBitSetAllocator<T>.Mask); }
 
 		public bool Equals(LongBitSet<T> other) { return other == this; }
 		public override bool Equals(object obj) { return obj is LongBitSet<T> && Equals((LongBitSet<T>)obj); }