The CW decoder was wrongly producing a Short Pause symbol instead of a
dot symbol. With this fix the decoder can now reconstruct the initial
text sequence sent.

Also the CW matched filter now can directly produce the power of the
filtered samples. This is very handy in order to get rid off an
additional multiply block, saving vital resources especially for
embedded platforms.

For testing and demonstration purposes the morse_decoding_flowgraph can
be used. The word sequence is the `HELLO WORLD`.