This gets FileDialog updated and working on Windows. It also
removes removes the "wx3" build configurations and makes the default
Debug and Release builds wx3-only.
Still need to get VSTs updated.
As this is a reversal of change committed in 2007 with no real
explanation or history behind that change other than it was
done for Export, we should probably give exporting a bit of a
workout.
We can't go to 3.0.1 yet as there are still build issues on
Linux and OSX. You can get Windows to build, but there's
still some display issues.
These changes should work with wxWidgets 2.8.12 as well, so
we can take our time to get things working properly before
switching over.
