Add helper functions "import_from_aud" and "export_to_aud" to
de-deplicate common code in tests.
The export functions reads back the exported signal to remove the impact
of quantization errors during wav export from test results.
Signed-off-by: Max Maisel <max.maisel@posteo.de>
This is based on my old loudness effect prototype which was included
in the Normalize effect.
Create all source files and add them to all build systems.
Currently, the effect only consists of a GUI mockup.
Create Octave+mod-script-pipe based dummy unit-test as well.
