Implementation of Pod::Simple::Select (RT #41995)

I have implemented the equivalent functionality of Pod::Select (now being discouraged) into Pod::Simple::Select. This addresses RT bug #41995: https://rt.cpan.org/Ticket/Display.html?id=41995

To keep things manageable, I have added a "raw_mode" in Pod::Simple::Blackbox. This mode forces Pod::Simple to parse very lazily and report entire, raw Pod lines. I then implemented a module called Pod::Simple::Select that is a subclass of Pod::Simple and uses this raw mode. Some tests were written as well.

There is an object-oriented and functional interface. The functional interface to this module has a single function, podselect(), that is a drop-in replacement for the Pod::Select::podselect() function.

Best,

Florent