Abinit: Added package(s) (#1995)

* First version of Abinit package

* Ignore *.swp files

* Add libxc, etsf_io packages

* AtomPaw package

* Make Abinit depend on mpi@2: and external version of libxc, netcdf, hdf5, etsf_io

* etsf_io: install Fortran modules in prefix.include

* Remove etsf_io from abinit requirements

* Add libxc2.2.1 (required by Abinit and atompaw)

* Cleanup

* Run make check

* Cleanup

* Use ld_flags instead of hard-coded libs, fix pep8, add copyright

* Put scalapack before lapackblas