.appveyor.yml: use pip to install test dependencies to work around issue with unittest2 on Windows:
.appveyor.yml: use pip to install test dependencies to work around issue with unittest2 on Windows:

See issue:
https://code.google.com/archive/p/unittest-ext/issues/95

Appveyor build error:
https://ci.appveyor.com/project/greginvm/pyclipper/build/1.0.13/job/9blrl0jsss9mlfee

greginvm/pyclipper,anthrotype/pyclipper,anthrotype/pyclipper,greginvm/pyclipper,anthrotype/pyclipper,greginvm/pyclipper