More template functions for `Entity` objects.
More template functions for `Entity` objects.

The following new functions are implemented (not tested yet):
`int32_t get_number_of_child_types(T1 entity)`,
`int32_t get_number_of_children(T1 entity)`,
`uint32_t get_number_of_descendants(std::vector<T1> ` ...
    `child_pointer_vector)`,
`uint32_t get_number_of_descendants_of_entity(T1 entity)`,
`InfoStruct* get_info(T1 entity)`.

All tests pass.

	modified:   code/ylikuutio/ontology/entity_templates.hpp

nrz/ylikuutio,nrz/ylikuutio,nrz/ylikuutio,nrz/ylikuutio