c++: use more explicit types than int

c++: use more explicit types than int

* data/c++.m4 (b4_public_types_declare): Declare token_number_type soon.
Introduce symbol_number_type (wider than token_number_type).
Clarify the requirement that kind_type from by_state and by_type
denote the _input_ type (required by the constructor), not the stored type.
Use symbol_number_type and token_number_type where appropriate, instead
of int.
* data/lalr1.cc: Adjust to these changes.
Propagate "symbol_number_type".
Invoke "type_get ()" instead of read "type" directly.