Model scene rendering

The substance of this change is to render all entities in a single gpu batch instead of each model in a different batch. The other major change is that instead of rendering each of the 24 possible shaders for each model then going to the next model, we now render all the models for each shader then go to the next shader. The result should be a performance improvement for large numbers of models.

However, I have defaulted this new mode to off for now, because I want to double check with Sam about how his new transforms cache can best be utilized in this mode. As it stands now we still have to switch the transforms for each model.

* Renders all entity models as a "scene" this basically means we don't switch shaders between each model. Since shader switching is expensing on our gpu pipeline, this should improve frame rate for scenes with lots of entities. - **NOTE: Defaults to off right now, want to double check with Sam to see if this works with his latest batch work.**

* splits out AnimationHandle class from the Model.h/cpp files to be compliant with coding standard