- Introduced `getStateHessian`, `getControlHessian`, and `getCrossHessian` methods across various dynamical models, returning vectors of matrices for Hessian calculations.
- Added a new example `hessian_example.cpp` demonstrating Hessian computations for pendulum and Dubins car models.
- Updated CMakeLists to include the new example and corresponding test file.
- Implemented unit tests for Hessian calculations in both pendulum and Dubins car models.

- Configured CMake to include the autodiff library, disabling tests, examples, and Python bindings.
- Added a new test executable for autodiff functionality, linking it with Google Test.
- Implemented comprehensive tests for autodiff, covering scalar functions, multivariate functions, and gradient comparisons with finite differences.

…ons and add autodiff library reference

- Introduced a new test file `test_autodiff.cpp` to validate autodiff operations.
- Implemented tests for scalar functions, multivariate functions, and quadratic forms.
- Included comparisons of autodiff gradients with finite difference methods for accuracy verification.
- Utilized Google Test framework for structured testing and output of results.

- Added support for autodiff in the DynamicalSystem class, including methods for computing Jacobians and Hessians using second-order duals.
- Implemented default versions of getStateJacobian, getControlJacobian, getStateHessian, getControlHessian, and getCrossHessian, leveraging autodiff for accurate derivative calculations.
- Updated comments for clarity and consistency regarding the use of autodiff in dynamics computations.

- Implemented the `getContinuousDynamicsAutodiff` method in the Bicycle class to compute continuous dynamics using autodiff with dual2nd types.
- Updated the header file to declare the new autodiff method.
- Enhanced the dynamics calculations to leverage autodiff for accurate derivative computations.

- Implemented `getDiscreteDynamicsAutodiff` and `getContinuousDynamicsAutodiff` methods in the Car class to support autodiff for discrete and continuous dynamics using dual2nd types.
- Updated the header file to declare the new autodiff methods.
- Included necessary headers for autodiff functionality and enhanced dynamics calculations for accurate derivative computations.

…namics model