Release 0.5.0

• Python 2.7 is required (earlier versions are not supported anymore)
• Support for Gromacs 5.x is now the default
  • You can use custom driver prefixes such as gmx or gmx_mpi in your gromacswrapper.cfg file to customize the tools that are being made available.
  • Gromacs 4.6.x still works. typically, GromacsWrapper scripts ought to be able to either use Gromacs 4 or Gromacs 5 because a number of compatibility hacks are included that make Gromacs 5 tools also appear under Gromacs 4 names.
• Removed GridMAT-MD and gridmatmd plugin (no demand and thus no longer supported)