Creation of the class Player
Update of the class ClickToShoot
Update of the class Position
Update of the class Target
Update of the class Grid
Update of the class Main

The class Player make us able to simulate a click on the screen

The update of ClickToShoot bring the generalization of the source for
the click

We added a constructor in the Position class to create a position with
the coordinates as parameters

We fixed the TODOs in the Target, Main and Grid class