* Promote to Autotools for simplicity; broaden Intel CPU opt targeting from SSE4.2 to AVX2
* make Intel CPU opt targeting same as in ../libxc
* flake8 W291
* use canonical means to pass (ahem) the test phase, h/t @adamjstewart
* revert f25d598 (unrelated merge)
* re-merge
* Initial work on flag trapping using functions called <flag>_handler and default_flag_handler
* Update packages so they do not obliterate flags
* Added append to EnvironmentModifications class
* changed EnvironmentModifications to have append_flags method
* changed flag_val to be a tuple
* Increased test coverage
* added documentation of flag handling
* 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
* Add libint package
* Add Intel optimization flags recommended by CP2K
* Add new version and Intel compiler optimization flags for libxc
* Add older version of libint
* Libint depends on GMP C++ library
