Strategy of loading resources

[aneteanetes]

Info

Need add another loading resources strategy.

Now

In Draw method, each ISceneObject.Image loads from cache "on the fly".
It works good for UI objects like windows (they may not opened at all) and when count of ISceneObject at scene not much.
But its not working for save/load or loading a lot of information from DB (especially, not images).

Proposal

By steps:

1. Add ISceneObject.LoadResources() method with return type IEnumerable<string> or something
2. Add IScene.LoadResources() and call it after SceneManager.ChangeScene
3. In Scene.LoadResources take all created objects (in init method) and call all tree of LoadResources() in each ISceneObject
4. Load all resources through ResourceManager, for not breaking current logic of loading resource into current IScene

Important

Current pipeline and logic must be save for UI windows or other things with low resources, and for some logic in ISceneObject constructors where ResourceLoader can load some json data - now it's done "in the background".