In this PR, I have created the Python bindings code for these three important classes. Additionally, we have the following contributions:
- Python code for testing inheritance (in Python world) of solvers.
- Custom converter between Python list to std::vector, and vice-verse.
- Added unit-test code for testing Python bindings of ShootingProblem and SolverAbstract.
- Clean up the code format.
- Few important overloading in SolverAbstract, ActionModels and SolverDDP.
This PR tackles the issues #174 (closed) and #173 (closed).