centered and mouse mouvement

Camara is centered to point the 0,0,0 at the begining, the matrix is
created keeping the 0,0,0 point at the middle.

Mouse mouvement added, and a variable to stablish the top mapped value
(at the end this is the speed). Limits are stablished automatically.

Next Up: comment everything, set numbers to the cubes to keep track of
them