When calling opengeode-simulator, will display the OG logo in place of
the TASTE logo, and disable the list of MSC scripts

It is not possible to share the stack between SDL and MSC handlers, they
live in separate threads.

Depending on the state of the SDL model, some buttons for sending
messages are now disabled, if the messages are not explicitely handled
by the model.

Reuse the ASN.1 Editor tree view to display the shared library internal
variables.

The SDL handler is parsing the SDL file, so it can read the list of
declared variables. Using the shared lib it can then read the actual
value of each parameter at runtime. An event (signal) is received by a
slot when an message (call of a PI) has ben processed. This is the
placeholder to put the read of the DLL.