* Add python 3.7 to travis and tox
* Use pyyaml from github
* Don't version constraints
* Fix version tag
* Change to new pyyaml release
* Python 3.7 requires xenial
* Fix namespace detection
* Use correct RegEx type
* Update pexpect to 4.6
* Use correct validation for dictionaries
* Disable Py37 incompatible packages
* Upgrade all pexpect to 4.6
* Add explicit None as default param