Travis yaml config: https://travis-ci.org/MarcoFalke/bitcoin/jobs/273753292/config

The pyenv advertises python3 (versions 3.4 and 3.6), though the call to python 3.6 fails:

pyenv: python3.6: command not found
The `python3.6' command exists in these Python versions:
  3.6
  3.6.1