In CoreGraphicsPixelData::createImage, image data was copied from a
BitmapData created from the Image passed into the function.

The BitmapData instance didn't keep track of the size of the buffer it
pointed to, so the buffer size was computed by multiplying the
BitmapData height by its line stride. However, if the BitmapData pointed
to a subsection of an image, the `data` pointer might be offset from
the allocated region, and `data + lineStride * height` would point past
the end of the allocated region. Trying to read/copy this range would
cause a heap buffer overflow at the end of the range.

This change adjusts BitmapData so that it keeps track of the size of the
allocated region. Taking a subsection of an image should subtract the
data pointer offset from the size of the allocated region.

The bug was triggered on Monterey where a pressure of 1 is reported
while a mouse button is being held down. This caused an extra drag
event being triggered between mouse down and up events, even if no
movement occurred.

This new factoring is a bit more typesafe, as it avoids casting
internals to void*.

It also allows cursors to scale appropriately on high resolution
displays on Windows.

- 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

The default main JuceActivity for JUCE apps calls appNewIntent() in its onNewIntent() implementation which is defined in juce_gui_extra. This commit moves the implementation into juce_gui_basics.

Please see the forum post "Re-structuring of JUCE’s low-level Android code" and the BREAKING-CHANGES.txt for more information.