Adds STATIC_H3D flag to create static libs.

Removed EngineOptions and EngineStats structs and now uses H3DOptions and H3DStats instead (they are same, and API docs and C# uses these too).

To create and link with static libs:
* add STATIC_H3D to Horde3D,Horde3DUtils (+extensions) and your own project's
Preprocessor settings.
* Change .dll -> .lib (Target extension and Configuration type).
* Static libs will be compiled in different directory so change paths.
Recompile all.