cleanup, remove overrides of dock widget topLevelChanged which worked…

[RussBerg]

… fine on windows but does not on Linux

• cleaned up unused/commented code
• removed dockwidget overrides for topLevelChanged signal, worked on windows eventually seg faults on linux/wayland/X11

[RussBerg]

The behaviour of the dockwidgets:

• If undocked and the user clicks off of the pyStxm app the undocked widgets disappear but re-appear when pyStxm is again selected.
• If undocked and closed the dockwidget can be made visible again by selecting it from the View menu, it will reappear where it had been previously been when it was closed.
• To redock it into pyStxm double click on the title bar of the dockwidget.