Merging dev branch for v0.0.5

Changelog

• Add packaging for Ubuntu Bionic (18.04), used by Google Colab
• Add license file
• Adds error file path to replace sys.stderr due to colab issues -> stdout and stderr to point to the same file
• Seed in reset_hard modified
• Poller removed
• State variable upper bounded
• Rewards adjusted
• Preinstall specific versions of pip, setuptools and wheel in dh-virtualenv
• ADD version attribute