5f7ad995af introduced an issue where the
string of external libraries would be escaped in one go. This is
incorrect, because only the individual paths should be escaped. The
semicolons separating each path should not be escaped.

Without the BOM, VS assumes UTF-8 strings (subproject file names etc.)
are ansi-encoded.

AU and AUv3 plugins only support version numbers with up to 3 parts.

- Add AlertWindow::show() and showAsync() methods that take a MessageBoxOptions argument
  - Add NativeMessageBox::show() and showAsync() methods that take a MessageBoxOptions argument
  - Update the DialogsDemo to demonstrate the new methods
  - Deprecate AlertWindow::showNativeDialogBox() in favour of the NativeMessageBox methods
  - Pass button strings specified in MesssageBoxOptions to native dialog boxes correctly
  - Use modern TaskDialog on Windows for the native dialog box where available

See BREAKING-CHANGES.txt for more details.

When building a static library, VS2019 replaces the generated link pdb file with the one created during compilation due to a broken copy step in Microsoft.CppCommon.targets. This workaround generates the pdb in the output directory so the copy step is skipped.