New Features
- Added `line_weakener`, which creates a mutator that reduces the amp rating of lines via a catalogue of line types.
- Added `transformer_weakener`, which creates a mutator that reduces the VA rating of transformers via a catalogue of
transformer models.
Breaking Changes
- The `seed` parameter has been moved to the usage point allocator creator.
- The `create_synthetic_feeder` method no longer returns anything. Each mutator function creator takes a callback to use
on a collection of information about the modified objects. The structure of this collection may vary between each
mutator.
- `create_synthetic_feeder` now takes multiple mutator functions in the `mutators` parameter.