Update code to run under Python3 + Conda packaging
- Updated to work with Python 3
- Added a unit test to ensure basic functionality of coverplot.get_command_args()
- Updated list of platform specific dependencies to be installed when installing coverplot in dev mode (see setup.py)
- Installed and tested coverplot against Python3.[6,7,8] using tox
- Formatted Python code to conform to the PEP8 style guide
- Created conda packages for coverplot that can run on Python3.[6,7,8]
- Updated .gitlab-ci.yml to run a linter and unit tests for Python3.[6,7,8] in GitLab CI pipeline