Fix issue with fallback in GetMachineCode

Update setup.py

Update setup.py

Update setup.py

Add more return fields to GetKeys method

Add Get Customer Licenses (#70)

* Update methods.py

* Update setup.py

* Update methods.py

Add "AddFeature" and "RemoveFeature"

Add new methods related to a License Key (#68)

* Update methods.py

* Update methods.py

* Update methods.py

* Update setup.py

Add support for Metadata property in Key.Activate (#67)

* First commit

* Update

* Update internal.py

* Update internal.py

* Update models.py

* Update setup.py

Update README.md