Worked around an apparent bug in Windows whereby some deferred positioning

Worked around an apparent bug in Windows whereby some deferred positioning
failed: specifically when changing a position from x, to y, to x again.
Added deferred positioning to wxRadioBox, wxSlider and wxSpinCtrl and thereby
eliminated some refresh glitches when resizing.
Eliminated further refresh glitches caused by wxRadioBox (to nearby controls)
by refreshing parent when the radio box moves.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@33907 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775