Python 3 support #38
Description
With the end of support for Python 2 coming up, it would be a good time to make sure GPX is compatible with Python 3.
Debian is currently removing all packages from the unstable distribution that depend on Python 2. Since gpx is packaged for Debian, it would mean that gpx will be going away soon, unless the Python parts can be removed or made compatible with Python 3.
What needs to be done to make GPX not depend on Python 2? Is it already compatible with Python 3? Is some porting work needed?