(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!

Now within the help system we can link to other topics.

A dash has been allowed in keys for a while now

Now the tab close confirmation works again.
(you must delete your settings file)

'Quit' does not send a closeEvent, so do it in the destructor.

Now child windows' close entries are named better (close preview, close help)
and fit next to the main "quit inishell" menu.

Since we have a unified main menu, we do not want to add 'About' twice

Intermediate commit - to tune and to re-fix on other platforms

Now numbers are correctly incremented when reading from ini files and
then clicking "+"

Clearing dynamic panels was not respecting the message box result

With recent changes we can just not exit out early and let the
SectionTab find the right index.

Now the user can individually turn off the confirmation dialog for when
a) an application has been opened, nothing was changed, and it is closed
again
b) an INI file has been opened, changes were made, and the application
is closed

This is nice because one of the messages could be annoying while the
other could be quite useful.

In addition to the command line --clear there is now a GUI button for
this.

But - allow not to warn again.