- added a way to terminate QThreads safely by waiting; should be much safer
- made sure that the ArgsThread class receive the signal to stop
- made sure that on application shutdown, all workers will quit before the actual exit
- fixed a number of issues, mostly leftovers from moving the UI of a Plugin in its own class
- fixed some bugs in the Punch Gerber plugin
- fixed some bugs where the 'pool' parameter was not passed when creating shapes collections (in 3D graphic mode); I wonder how it worked until now
- added a new feature in the Isolation Plugin: now for all the isolation Geometry objects this plugin can do a supplementary simplification of the geometry using the tolerance parameter defined in the General Parameters. This should lead to a reduced number of tool lifts when doing corners
- fixed some outstanding issues from the PyQt6 port
- PEP8 fixes
- minor fixes
- updated the saving of Preferences to update the self.options too: the `Apply` action will update the self.options but the `Save` action will save the updated preferences to the file on disk
- some refactoring
- in a FCColorEntry GUI element, setting a color in the Color dialog will trigger the editingFinished signal therefore propagating the changes
