Also start on making package functions accept Lisp strings instead
of std::strings. Using std::strings means no support for extended
strings, which is pretty dumb.

not every place, though. still working on it. but this is another
step towards not assuming package names are base strings.

and, bonus? Less stupid consing.

This fixes the FASO build.

I'm leaving in the string one since we probably use it during boot
or for extensions or some crapola like that.

__repr__ is still broken but it's kind of dumb anyway. To fix it
we'd have to make it not return a std::string, I guess, which
would be a pretty severe change.

Previously it tested if the name was "", but that doesn't work
well given character strings, or the pathological case of an empty
name. We already have a "deleted" flag so we may as well use it.