Don't add NSFunctionKeyMask to NSMenuItem modifiers.

This code probably misunderstood NSEvent documentation, where this mask is
mentioned, but setKeyEquivalentModifierMask: documentation doesn't list it as
allowed. More importantly, it causes "fn" to appear in the menu item and the
accelerator doesn't work.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@75276 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Differentiate between WXK_UP etc. and WXK_NUMPAD_ variants in NSMenuItem code.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@75277 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Recognize Windows 8 and 8.1 in wxGetOsDescription().

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@75278 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775