Considerable extension of regresion tests
Last version based on python 2.
i-PI version 2.0.0 As archived with the publication: https://doi.org/10.1016/j.cpc.2018.09.020
i-PI version 1.1.0 Two new tools and some minor modifications
i-PI version 1.0.0 As archived with the publication: http://dx.doi.org/10.1016/j.cpc.2013.10.027