Slightly modernize / improve the GROMACS interface (#132)
Slightly modernize / improve the GROMACS interface (#132)

* Remove py2 / py3 workaround for string detection (refs #47)
* Replace os.errno by actually importing errno (see
  https://github.com/python/cpython/commit/1d2dafa249c7fb34f3d24e7a77d1bea02907d92b)
* Remove py2 workaround defining the encoding, which makes newer
  versions of py3 fail
* Add default location of GROMACS topology library, which will make
  use of bioconda gromacs in tests possible
shirtsgroup/physical-validation