Improved naming in BoxGeometry 

 The variable names of BoxGeometry has been updated for greater consistency. Thus there is a clear distinction between the 'global' 3D space of x, y, z and the 'local' 2D space of u, v. ...and some other naming improvements
Hmmm... `var scope = this;` is kind of a pattern used all over the lib. Probably better not to change this one.