Undocumented methods for Unit class

The following Python methods are currently not documented:

        .def("use_ability", &IDABot::UseAbility, "Use an ability with the given unit")
        .def("use_ability", &IDABot::UseAbilityWithPoint, "Use ability at point with the given unit")
        .def("use_ability", &IDABot::UseAbilityWithTarget, "Use ability at target with the given unit");