... Though in the only place where these summaries are used, which is
Sequence::GetWaveDisplay, we ignore the correctly reported error code anyway.
Also RAII in management of relevant memory buffers and mutexes.
... whenever they really describe the size of a buffer that fits in memory, or
of a block file (which is never now more than a megabyte and so could be fit in
memory all at once), or a part thereof.
... for functions in final classes.
override is like const -- it's not necessary, but it helps the compiler to
catch mistakes.
There may be some overriding functions not explicitly declared virtual and I did
not identify such cases, in which I might also add override.
... 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.
Basic problem was in using wxConvUTF8 instead of wxConvFile. I believe wxConvFile should work on all platforms, but if not we can "#ifdef _WIN32" its use.
Also simplified the code by getting rid of the mFileNameChar member. It was used only in ODPCMAliasBlockFile::WriteSummary() so there's no reason to do the conversion from mFileName in so many places -- just do it once, in ODPCMAliasBlockFile::WriteSummary().
