orbeckst, PolyachenkoYA, whitead
* confirmed support for GROMACS 4.6.5, 2018, 2019, 2020, 2021 on Python 2.7 and
3.6--3.9 on Linux and macOS (200, 202, 203)
* fixed: core._run_command capture_output_file argument fixed to us python-3.0
file open (181)
* fixed: xvg._decimate used python-2.0-specific func_name() (issue 183)
* fixed: make parsing gmx output more robust to avoid failure on
'import gromacs' (PR 186)
* fixed: xpm.to_df() used outdated convert_objects()
* fixed: gw-forcefield.py use print() function for Py 2/3 compatibility
* fixed: xvg.plot() and xvg.plot_coarsened() failed with Py 3 matplotlib
due to incompatible colors (issue 194)