Several fixes and improved performance

This version has several fixes:

• reflection / refraction water fixes
• renderers per renderpass fix
• particles reflection fix
• grass refraction fix

Grass

New release
Includes:

• improved performance on shadows due to depth texture resolution reduccion
• MaterialEffectShadowProperties can specify the pfcCounter for shadows
• New PointsPatchEntity to specify a set of points and apply any shader
• Grass implementation with movement, and Modificators
• EnvironmentSystem to controll wind
• Wind map

QuadTrees

Now the game is using a quadtree space partition code.
With space partition we can avoid render all entities and only those that ara inside the camera volume.
That way, reflection, refraction and gameplay are only rendering the renderers whose entities are inside the camera volume and shadows is using all renderers because we want to render shadows of entities outside the camera volume (this can be improved).
Then, is possible to setup each RenderPass to accept or not space partition renderers.
The quadtree implementation has a fast addition and removal what means the quadtree can support dynamic entities.

Added a IMaterial to the IRenderer

Big refactor. Adding IMaterial and MaterialEffects, to allow render a Renderer with any Material.
Also, added the Model to the Renderer.

First version

This version contains:

• terrain generated with a terrainmap with blending between 4 materials and tile repeating improvement.
  Also casts shadows.
• particle emitters. Soft particles. Billboard, transparency and ordered in z. Instancing.
• obj models rendered with instancing. Casting shadows. With different levels of detail.
• water. With reflections, refraction, and fresnel effect.
• energy wall collision and rendering. Used as a world limit and colliding with player. Marking with a white line the collision with ground.
• lighting
• fog
• 3D text, and GUI text
• GUI quads
• skybox