FIX: Non-client windows using rendering surface were clipped to client area.
FIX: Non-client windows using rendering surface were clipped to client area.

--HG--
branch : v0-7

cbeck88/cegui-mirror-two,cbeck88/cegui-mirror-two,cbeck88/cegui-mirror-two,cbeck88/cegui-mirror-two,cbeck88/cegui-mirror-two