Move down code into folder

mbtrack2/__init__.py

mbtrack2/impedance/__init__.py

mbtrack2/impedance/csr.py

mbtrack2/impedance/impedance_model.py

mbtrack2/impedance/resistive_wall.py

mbtrack2/impedance/resonator.py

mbtrack2/impedance/tapers.py

mbtrack2/impedance/wakefield.py

mbtrack2/instability/__init__.py

mbtrack2/instability/instabilities.py

mbtrack2/instability/ions.py

mbtrack2/tracking/__init__.py

mbtrack2/tracking/aperture.py

mbtrack2/tracking/element.py

mbtrack2/tracking/monitors/__init__.py

mbtrack2/tracking/monitors/monitors.py

mbtrack2/tracking/monitors/plotting.py

mbtrack2/tracking/monitors/tools.py

mbtrack2/tracking/parallel.py

mbtrack2/tracking/particles.py