Command sequence for parameterized model is suboptimal

Need exactly this:

```python
model = ParameterizedBrightwayModel("teddy_bears")
model.load_parameter_data()
model.calculate_stochastic(iterations=1000, update_amounts=True)
model.calculate_matrix_presamples()
_, filepath = model.save_presample("fidget")
```

There are some non-default options and other weirdness here. Need to document and make more sensible.