Minor fixes, symlink and venv

I needed/ran the following to get amodem running in my environment: 

```
sudo apt-get install python-dev python3-pyaudio python-pyaudio-doc
sudo ln -s /usr/lib/x86_64-linux-gnu/libportaudio.so.2 /usr/lib/x86_64-linux-gnu/libportaudio.so

python3 -m venv ~/ve_amodem
. ~/ve_amodem/bin/activate
pip install wheel
python setup.py bdist_wheel 
pip install . 
```