Python 2.7 EOL is arriving on 2020-01-01: https://pythonclock.org/
This will allow us to use Python 3 only libraries, like python-barcode,
which can maintain a reduced, simpler codebase, due to only one version
to support.
Closes#371.
Signed-off-by: Romain Porte <microjoe@microjoe.org>
This was tested on ZJ-5890 with success. By default centering is
deactivated for backward compatibility. Trying to center a QR code in
native mode will raise an exception as we do not know ATM if the native
rendering is centered by default or not.
* Added basic tests for center feature
* Check image size before centering