Previously, the child process could be deleted from its own
handleConnectionLost() callback, which would attempt to stop the child
process's thread from that same thread.

Now, the demo will attempt to stop the coordinator thread from the main
thread instead.

Some Windows 11 devices have both touch screens and mouse inputs, and
these can be used simultaneously.

The Viewport (and ListBox) now check the input source of each mouse
down. If the source is not a mouse, the viewport will always enter
drag-to-scroll mode, regardless of the result of isScrollOnDragEnabled.

This commit removes the various compiler-specific JUCE_DEPRECATED macros and replaces them with C++14's deprecated attribute. It also removes the JUCE_CATCH_DEPRECATED_CODE_MISUSE flag as we can rely on the override specifier catching usage of these old virtual methods, and tidies up the DOXYGEN preprocessor checks as they were inconsistent across the codebase.

- 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

This fixes warnings that are emitted when building with the `-analyze`
flag enabled.

The PushNotificationsDemo is not supported on Windows, so I've
stopped CMake from configuring it in the first place.