As a gRPC User I want to get info about names and pages given a set of titleIDs

[dimus]

Stream(or return?) pages/names data according to a stream (or array?) of title ids.

[dimus]

I am going to do a significant refactoring for this ticket and break backward compatibility, gladly not many people use our protobuf interface so far. It is interesting design decision that protobuf always takes one 'argument' and always returns one 'argument', so basically for not breaking backward compatibility it seem to be important to always give a structure with some neutral name as an input like PagesOpts or something like that.