Two more standard examples for type wrapping and InternalFunction

Here are two of the test files I used to get familiar with some of the concepts I needed. I've cleaned them up and commented everything.

Adding a pull request in the hopes that the next person starting on similar problems may find them useful. Feel free to commit or reject as you like.
Otherwise lovely work which I really appreciate!   

Oh, but look into adding something in `ChangeLog` at the top of the repo too.   And possibly also `inst/NEWS.Rd` -- credit where credit is due, and you should get yours.