Allow multiple enum values to be parsed from yaml with the same syntax as a string[].

OpenRA.Game/FieldLoader.cs

@@ -263,10 +263,15 @@ namespace OpenRA
 
 			else if (fieldType.IsEnum)
 			{
-				if (!Enum.GetNames(fieldType).Select(a => a.ToLower()).Contains(value.ToLower()))
-					return InvalidValueAction(value, fieldType, fieldName);
+				try
+				{
 					return Enum.Parse(fieldType, value, true);
 				}
+				catch (ArgumentException)
+				{
+					return InvalidValueAction(value, fieldType, fieldName);
+				}
+			}
 
 			else if (fieldType == typeof(bool))
 				return ParseYesNo(value, fieldType, fieldName);