- Vertex shader variable "modelViewMatrix" renamed to "mvpMatrix" (ModelViewProjection).
- Removed some couts.
- Argument "Camera* camera" for methods "Drawable::draw()" and "Scene::draw()" has been replaced by "glm::mat4& viewProjectionMatrix". By doing this, the cyclic dependency between classes "Drawable" and "Camera" is gone.
	- TODO: Because projections and cameras are not fully implemented yet, Scene::draw() is called with a identity viewProjectionMatrix.
- Now class "Camera" inherits from class Cube. The idea is to make it inherit from Geometry (this way the camera will have its own mesh), but more changes are needed. This is a temporal solution.
- Now is the class "Drawable" who has access and updates previous shader variable "modelViewMatrix" (Before, these were responsabilities of class "Camera").
- Removed some unused methos from class Camera.
- Removed attributes related to Camera's center and up vectors. This vectors are kept in Drawable's orientation attributes.