This gets rid of an inconsistency where on macOS CMD+H was
already reserved for hiding the window. It's nicer anyway
and we get rid of an almost empty menu ("window").

Now we focus on the styling widget (usually the label), to scroll to the
beginning of the content.
(Otherwise the horizontal scroll bar would center)
Also: use the same color for frame and panel highlighting.

There were still crashes where a Timer was called on an invalidated
object. Now, this timer is in Atomic and therefore gets destroyed with
the widget.
This way we can have multiple stylings running and it is more logical,
cleaner, and more general purpose.

... of the main windows in place (unless of course the settings are
reset).

Clicking "reset" in the Settings window should now behave the same as if
the settings file was deleted manually before starting, i. e. restore
all defaults immediately.

For the styling timer we can not use the static version of singleShot,
because we must be able to stop it (when switching XMLs while something
is being highlighted).
Also, an INIParser object has been leaking

Now the user can choose to restart INIshell immediately if any of the
appearance settings have been modified when saving.

This layout should be well known and unsurprising to users, and the
ability to just cancel if something was changed by accident is also
nice.
Also, all windows now have reasonable minimum sizes.

Maybe something like this should also be done when saving...

Otherwise, window size settings etc. would be saved as-is on the next
program quit, making clearing these automatic position settings not
very effective (would have to go through command line args).

Namely "open parent folder" and "delete file"

This feature has been broken with a commit in April... now it should
work again.
I. e.: If unknown keys are read in, they will be shown (and highlighted
as invalid) in the Preview Editor and also saved back out to the file
system.

It should start again if the user leaves ${inifile} as working dir.

There are potentially two warnings the user can cancel (file exists
and unsaved changes); for the latter the internal file path would be
set even if the user has cancelled. This has been fixed.

This is now the same behaviour as for dynamic sections.

Before, it was tied to the "unsaved" warning when closing inis/XMLs,
but now the user can control this separately, hopefully encouraging
them to keep the more important ones.

We need this shortcut for the tabs, and this way CMD+Q quits the whole
application as is expected on mac.
We can still use this shortcut by repeating it until all tabs are closed
(and ESC also works).

They should not be marked as missing in the confirmation box if they
have children (even though the key "REP#" itself does not exist)

This is useful for example when looking for METEOPATH --> different
plugins will have different panels loaded --> highlight them all

Missing INI keys are now listed more user friendly. If the user cancels
out of saving, the first missing key is jumped to and highlighted in
Inishell.

This allows to still use ESC when a status message is displayed (like
"empty INI file") while keeping it working with the search text box

And minor cleanup

It was used to close the find bar but now just close them one after the
other... the Preview Editor was the only window this did not work for.

(Now the question remains how to handle Alt+F4 / CMD+Q --> on Mac it may
be expected to close everything?)

(also showcase it in the temporary test XML)

It can still either be a frame (border is flashed) but now also any kind
of input panel with it's respective key (it is highlighted for a short
period of time).

We can now link to frames within the main XMLs!