* Changed World closure into constructor function w/ prototypes
* Gave Cube a positionSelf() function
  * cube now has .mesh property, which is passed into render/setScene/etc
* Create instance of CubeFactory, marioFactory, to hold mario cubes.
* Create for loop to place all cubes from marioFactory in scene.
* Add cubePlacer method that places cubes according to index.
* Add x, y, z positional arguments to Cube positionSelf method.
Merge pull request #3 from mathildemouw/two-cubes

Place two cubes in the world from marioFactory