But the end is coming!

* Python 2 incompatibility
* Handle actual update, .remote_head_rev needs to be updated
  in that case

Hopefully not for long anymore..

In order to be able to figure out the matching MKL version for a given
compiler/MPI repository we emit a new macro '%matching_mkl_version' in
the cases this makes sense

Add macro compiler_repository to have early access to compiler name

See merge request !2