Wrapper for MPI_Intercomm_create

[fverdugo]

Dear MPI.jl team,

I have not found any wrapper for MPI_Intercomm_create nor in the documentation nor by grep-ing into de source code.

Is there a specific reason that prevents to provide a julia function for MPI_Intercomm_create? or it is simply because nobody has needed/implemented it so far?

Thanks for the nice package!

[simonbyrne]

or it is simply because nobody has needed/implemented it so far?

That's it: PRs welcome!