Updated VS12's Desktop Lib project.

- The Desktop Lib projecto of VS12 now references the gpud.hpp file.
Multiple updates.

- Added the prototype of GPUinfo's ctor and dtor.
- Added a few accessors regarding the current set of data members.
Added the early prototypes of the GPUs enumeration functions.
Multiple updates.

- Configured the x86 and x64 builds for Windows Desktop library.
- Implemented the current inline member function of GPUinfo.
- Added the gpud.cpp just for compilation purposes.