A matplotlib mini backend always base on the latest QT for Python, no compatible will be care

Focus on Qt 6 (will always point to the latest) for Python and QML/QWidget as main user case, only desktop application will be care

Mainly base on:

1. https://github.com/jmitrevs/matplotlib_backend_qtquick
2. https://github.com/matplotlib/matplotlib/blob/master/lib/matplotlib/backends/backend_qt5.py
3. https://github.com/matplotlib/matplotlib/blob/master/lib/matplotlib/backends/backend_qt5agg.py

The module can run as qml demo application itself, like:

    python -m matplotlibqml    

A standalone classic QWidget sample(pure QWidget) is provided too, like:

    python -m matplotlibqml.widgetdemo

你好

Why

QT keep improving and changing, and compatibility will kill flexibility, especially when upstream not so stable

Credit:

1. https://github.com/fcollonval/matplotlib_qtquick_playground
2. https://github.com/jmitrevs/matplotlib_backend_qtquick
3. https://github.com/matplotlib/matplotlib/blob/master/lib/matplotlib/backends/backend_qt5.py
4. https://github.com/matplotlib/matplotlib/blob/master/lib/matplotlib/backends/backend_qt5agg.py
5. Some weekend play for fun self Python project