Added class 'boost::static_object_pool'. To minimize code duplication and prevent API changes, existing class 'boost::object_pool<T, UserAllocator>' now inherits from 'boost::object_pool_base<T, pool<UserAllocator>>'.
Member functions get_max_size() and set_max_size() where missing from boost::object_pool implementation. I took advantage of the refactoring to add these functions.