[RFR] Mutation interpolation

- [x] Pass which types of mutations are allowed in `network.mutation`
- [x] Interpolation helper functions

Mutation Distance Interpolation for 
- [x] `MutateConnectionWeights` ConnectionMutationRate and mutationDelta
- [x] `MutateNodeParameters` nodeMutationRate
- [x] `node` parameterMutation chance
- [x] `node` mutatableParameters

FM Connections
- [x] new ConnectableParam objects in all affected nodes
```
{
  name: <string>,
  nodeName: <string>,
  deltaRange: {
    min: [y0, y1],
    max: [y0, y1]
  },
  randomRange: {
    min: <number>,
    max: <number>
  }
}
```
- [x] new ConnectableParams used during fm `NoteOscillator` creation in `network.addOscillator`
- [x] to/from JSON work correctly?

Other
- [x] Tests