Move type operations to another structure

Every type has free, print, check_constraints, ber_decoder, der_encoder,
xer_decoder, xer_encoder, uper_decoder, uper_encoder and outmost_tag
operations. We move them out to a separate structure asn_TYPE_operation_t.

Combined with previous logic simplification, these operations are based
on ASN.1 basic types, constructed types and string types. So we can
reduce the space occupied by asn_TYPE_descriptor_t variables.
diff --git a/skeletons/IA5String.h b/skeletons/IA5String.h
index 0c6f018..fa9f7ac 100644
--- a/skeletons/IA5String.h
+++ b/skeletons/IA5String.h
@@ -17,6 +17,7 @@
  * IA5String ASN.1 type definition.
  */
 extern asn_TYPE_descriptor_t asn_DEF_IA5String;
+extern asn_TYPE_operation_t asn_OP_IA5String;
 
 asn_constr_check_f IA5String_constraint;