[Issue 252] Add type cast for default enum values in C#

When creating a “CreateXxx(...)” method for a “simple table” type,
enum-type fields with a non-zero default must have an explicit
cast for the respective argument default value, because in C#,
there is an implicit cast from int to an enum only for 0.

Also, added an example of such type into the example monster_test
type, so that we test this feature.

tests/MyGame/Example/Any.cs

@@ -7,6 +7,7 @@ public enum Any : byte
 {
  NONE = 0,
  Monster = 1,
+ TestSimpleTableWithEnum = 2,
 };