... Unnecessary because transitively included.
But each .cpp file still includes its own .h file near the top to ensure
that it compiles indenendently, even if it is reincluded transitively later.
... 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.
... instead use the utility make_iterator_range and its index() or contains()
method. This generic utility works with any container defining begin() and
end().
This further lessens dependency on wxWidgets container idioms.
... 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.
... Should have no effect on generated code, except perhaps some slight faster
virtual function calls. Mostly useful as documentation of design intent.
Tried to mark every one of our classes that inherits from another, or is a
base for others, or has abstract virtual functions, and a few others besides.
