Cleanup of internal organs

Both internal and external organs are a mess, which is making
maintaining and updating them nasty, so I'm cleaning them up, this is
the first stage

mechanical and assisted internal organs are now an object type rather
than a var in the organ which makes it much cleaner and easier to adjust

removed duplicate list of internal organs as there's no reason to have
the same objects in 2 separate lists

made New() a lot cleaner and more robust

External organs will be next