[csrss]

[csrss]
- Paint the desktop only when getting WM_ERASEBKGND message, and do nothing in WM_PAINT. This is the behavior Windows and Wine implement.
- Add WM_CLOSE stub-handler, though it doesn't change much now - all messages unhandled by the switch are going to return "0" since this proc doesn't call DefWndProcHandler.

svn path=/trunk/; revision=43934