string import dependencies

[Robert]

>
> If the output wasn't there in the first place wouldn't it be 
> possible to add new information in a backwards compatible way?

No, the format of the file does not allow that. Whether 
compatibility is a concern or not was not for me to decide. I 
assumed it is not a good idea to break tools this abruptly. I 
thought it would be better to add just a new way of getting 
dependencies (which has an extensible format, btw.), the old one 
can then be deprecated and removed sometime in the future.