* added reading/writing working version of new model format V3
* added CStaticObject with minial interface intended for
non-interactive static objects like trees
* converted first model, tree0, to new format
* refactored model loading code based on code from dev-models
* support new model format V2 (without LOD levels)
* removed LOD levels support in CEngine and from model files
* preparations for new model format V3:
- support for multiple meshes in one model file
- support for saving crash spheres and shadow spots
- removed all direct dependencies on CEngine enum values
- quantized model rendering states to new flags and enums
* remove unused functions and members
* make protected functions used only locally or in factory
* rename some functions to be more meaningful
* refactor some enums to enum classes
Piotr Dziwinski