Code cleanup.

Assets/Cryville/Crtr/PropSrc.cs

@@ -54,6 +54,7 @@ namespace Cryville.Crtr {
 				}
 			}
 		}
+		public static readonly PropSrc Null = new Arbitrary(PdtInternalType.Null, new byte[0]);
 		public class String : PropSrc {
 			readonly Func<string> _cb;
 			public String(Func<string> cb) : base(PdtInternalType.String) { _cb = cb; }