[core/python] Custom return policy to avoid conflits with external modules.
Small release fixing conflicts with external Boost.Python modules, along some other minor bugs.
Bug fixes
- [core] Fix bug at Robot initialization when defining default flexible joints in the model.
- [core/python] Fix wrong keyword arguments for 'EngineMultiRobot.reset' method.
- [core/python] Add new Boost.Python return policy that can be used to by-pass converter registry if 'convertToPython' has been specified.
Miscellaneous
- [python] Add some missing typing return types.