... except Audacity.h
This forces us to make each header contain all forward declarations or nested
headers that it requires, rather than depend on context.
... for wxString and wxArrayStringEx, holding file paths (absolute or relative,
directory or plain file); to be replaced later with different types
(not yet using std::vector, becase of some uses of wxArrayString::Index with
two arguments)
... and similar wx "variadics," which all treat wxString smartly enough that
you don't need this.
Don't need c_str either to convert wxString to const wxChar * because
wxString has a conversion operator that does the same.
