Renamed gpud_helper.hpp to gpud_macros.hpp. Updated all refs.
First update towards the new interface.

- The diferent methods of acquiring information about the system's
GPUs return significant different results. Therefore each approach will
now have its specific return type.
Multiple updates.

- Renamed gpud_macros.hpp to gpud_env.hpp. Updated all the refs.
- Renamed the GpuWmi class to GpuInfoWmi. Updated all the refs.
- Defined the interface and data members of GpuInfoWmi.
Renamed GpuInfoWmi to WMIUnit.
Implemented the inline member functions from WMIUnit.
Multiple updates.

- Fixed some minor mistakes.
- First full implementation of WMIUnit.