Fix the scripts to pass the XML validation.

Remove references to the Ubuntu Xenial release as it is no longer sup…

…ported by GitHub.

Always set useDefault to false when calling SGPropertyNode::tie()

See issue JSBSim-Team#363: setting `useDefault` to true is equivalent to have uninitialized variables.

Distutils no longer places double quotes around compiler flags (Pytho…

…n 3.9 for Windows.)

Build a source package for JSBSim Python module compatible with all p…

…latforms (Windows, MacOSX, Linux)

Until now, the CI workflow was building 2 different source packages (1 for Windows and 1 for MacOSX/Linux). Unfortunately, PyPI allows only one source package to be uploaded. This commit allows to produce just one source package that is compatible with all platforms.

Fix the generation of the Python API docs

Reported in issue JSBSim-Team#373.

Remove outdated comment from FGPropeller

Generate the Inno Setup file

...and bump the version back to 1.1.1 (Oops !)