New reference added to ./docs/

Signed-off-by: Eduardo Tenorio <embatbr@gmail.com>
Changing tests for features/sigproc.py

Signed-off-by: Eduardo Tenorio <embatbr@gmail.com>
Auxiliar function concat_frame + test improved.

Signed-off-by: Eduardo Tenorio <embatbr@gmail.com>
Test improved.

Signed-off-by: Eduardo Tenorio <embatbr@gmail.com>