Blender Git Loki

Fix T70991: Maximized file browser hides file name bar on Windows

`WS_CHILD` is a different kind of child window that what we define as
child window. See http://forums.codeguru.com/showthread.php?491604.

Setting this style flag seems to mess things up a bit in our
configuration. The name bar is actually being overlapped by the Windows
task bar then. Not totally sure why this happens, but I think it's
because windows with the `WS_CHILD` style are positioned relative to the
parent, not the desktop (screen without taskbar). So it uses the full
space available when maximized, which isn't clipped by the taskbar
anymore.