Rename GDIDEVICE to PDEVOBJ. Is seems ms uses both PDEV and PDEVOBJ, whith the latter...

Rename GDIDEVICE to PDEVOBJ. Is seems ms uses both PDEV and PDEVOBJ, whith the latter being the C++ representation. But we don't use C++ and PDEVOBJ seems to be a more appropriate name, as PDEV is often used by display drivers.
Make DC.ppdev of type PDEVOBJ* and remove a bunch of typecasts.

svn path=/trunk/; revision=40137