We can check if the main window still exists with Exists() instead.
This may also have fixed the problem with joining all threads...

No other changes were made.

Wrap everything into an eval() to contain faults.
Fail to succeed for unknown reasons. Possibly because of the impossibility
to stop Perl:Tk from going berserk when the function does not set up
the widget correctly before returning?

Put download_worker code into eval and report its demise to the GUI
via $queue_to_gui.
This allows us to abort safely on fatal errors like missing packages (if
nothing else interferes... I am looking at you Tk!)
To that end install an afterIdle event handler that checks for said
message, displays an error dialog and exits the GUI when the user has
acknowledged the problem.

 - Switch is only used once in the code and easily substituted by some
   if-elsif-else clauses... thus remove it.
 - Add usage information to all other packages in the documentation
   where it was missing.

Most if not all of it should be covered by the instrumentation test set

The syntax of errors seems to be "@E|" instead of warnings that start
with "@W:" O_o

Covered in testcase_ASSIGN_PIN_bus_bus2single

access to clock, reset, trigger and fault detect nets during instrumentation

Covered in testcase_PIN_PIN_bus_bus2single

Previously we have only cleaned the instrumented netlists but that
make the log files grow forever...

This is needed to fix the first instrumentation of a vector when
instrumenting the second bit.

This reverts commit ec5fd76e414ec0f74b4b2dd4a75d1ae6dfe8f988.

This reverts commit 3efe7a8bf0e2e5f0c83a7e7f707fd5e183533b52.