Allow numeric aggregate converter to convert structures using MultidimensionalArrayConverter

The following converter should be supported:

```
[TypeConverter(typeof(MultidimensionalArrayConverter))]
public Point3f[] Points { get; set; }
```

Since `Point3f` supports numeric aggregate converter, the `MultidimensionalArrayConverter` could simply take the converter of `Point3f` and apply its own row separator `;` to create a compound converter for arrays of complex structures.