Now, with the Morse code debug source block the testing of the decoder
can begin.
Add at the examples directory a small flowgraph that connects the debug
source block with the decoder.
Depending the received symbol the tree is traversed towards the leafs.
At each step the corresponding decode-able character is appended at a
string buffer.
TODOs:
* Add logic in the decoder to retrieve the decoded words from the tree
* Create a debug source block