Added
- Add a new boundary condition for the `CatmullRom` class called `'clamped'`,
which allows anchoring the first and last points of the curve to the first
and last control points. This is particularly useful for smoothing
`MultiLineString` geometries where the first and last points of each
line segment must remain connected to the previous and next line segment.
Changed
- Freeze attributes of `CatmullRom` since they are not supposed to be changed,
once the class is instantiated. If needed, a new instance should be created.