Python bindings for vehicle_get_property

[juanmanzanero]

The C version of vehicle_get_property is

double vehicle_get_property(const char* vehicle_name, const double* q, const double* qa, const double* u, const double s, const char* property_name);

Provide a binding in python, with the form:

def vehicle_get_property(vehicle_name, inputs, property_name)

where inputs is a dictionary with all the required inputs (q, qa, u and s), which are written into their C version (const double*) inside the function. To do so, the program shall first inquire C++ the key_name, q_names, qa_names, and u_names (this needs to be implemented first)

The program should stop if a required variable is not present and if there's an unused variable inside the map.