Directives round 2

[pekkah]

Should be only on these locations in type system:

 public static IEnumerable<DirectiveLocation> TypeSystemLocations = new[]
        {
            DirectiveLocation.SCHEMA,
            DirectiveLocation.SCALAR,
            DirectiveLocation.OBJECT,
            DirectiveLocation.FIELD_DEFINITION,
            DirectiveLocation.ARGUMENT_DEFINITION,
            DirectiveLocation.INTERFACE,
            DirectiveLocation.UNION,
            DirectiveLocation.ENUM,
            DirectiveLocation.ENUM_VALUE,
            DirectiveLocation.INPUT_OBJECT,
            DirectiveLocation.INPUT_FIELD_DEFINITION
        };