Rework the wxCusor ctor taking wx stock number to provide as many cursors as

Rework the wxCusor ctor taking wx stock number to provide as many cursors as
possible by using the system cursors first, a set of built-in cursors copied
from wxMac if a system cursor was not found, and a normal cursor otherwise.

Fixes lack of wxCURSOR_HAND and makes the code easier to follow by clearly
showing which cursors are and are not available from each source.

Copyright 2007, Software 2000 Ltd.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@47581 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775