Update dependency versions #4
Description
Versions in http://mdp-toolkit.sourceforge.net/install.html#requirements and http://mdp-toolkit.sourceforge.net/install.html#optional-libraries look outdated. E.g. up to Python 3.8 is tested and supported, up to newest numpy,scipy work, very old numpys don't anymore, see https://github.com/mdp-toolkit/mdp-toolkit/blob/master/.travis.yml
The versions should be updated along with the upcoming release.