Previously Wintab packets were added to a local queue to be processed
during Win32 mouse events, in order to correlate Wintab to Win32
mouse buttons. Wintab packets before Win32 mouse down events were
expired on a timer.
This commit drives mouse events during Wintab events when a device is
in range. When a Wintab button is found it is dispatched if an
equivalent event can be popped from the Win32 event queue. If a Win32
mouse button event is not associated with a Wintab event, it falls
through to WM_BUTTON handling. All Wintab packets are handled as they
are received.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D9908