[Grace-core] Import statements

[Marco Servetto]

Dear Lex, you have very strong opinion on how dependency should be resolved.
I have too, but they are all sort of opposite w.r.t. yours...
Do you want to discuss more extensively on this problem? either on
grace-core or with personal communication? do you have some article I
should give a look to have a coherent background to talk over?
In particular, I really do not understand
>>3. URLs. You don't want your builds to make requests to third-party Internet sites.
why this should be true... all the internet application works that
way, and they work much better than any local dependency system....
yes, it means that you have to be connected to the internet to compile.
Is that sill a problem today?

Marco