If the same message was received twice by the msgQ poller before being displayed
by the GUI, one message could ve overwritten.
Now wait for the first message to be consumed before taking the next
one.

the new items are added to the list of items at creation time (needed
for the streaming scene). for the Redo, check that the last item is
there and if not, put it back

Automatic scroll up when streaming

Create a buffer for each received message.
There are unclear issues with the use of .raw with ctypes String
buffers.