Pull Request n°2

Content:

Add&update French translation for several files ( by using po4a )
Optimisation of the BaseballWorld in the SMN
Add the features to have more than two players per base in the BaseballWorld
Split the SlugHunting exercice in two ( according to the TODO file )
Simplify the random mouse maze ( issue #26 )
Add an interactive way to change the color of the buggle in the buggles exercises ( according to the TODO file )
Add an interactive way to change the color of the brush of the buggle in the buggles exercises ( according to the TODO file )
Move all the images and the map to the resources repertory
Add a basic Main.html & Main.fr.html for the lesson chooser
Add a confirmation window when you try to exit the JLM by clicking on the corner button ( according to the TODO file )
Replace the error message printed in the console by a dialogue windows when you hit a wall by using the interactive controls
Add a dialog window which appears once you've completed an exercice and it proposes you to selected the next exercice among the succesors of the current exercise. If there is no succesor to the current exercice, it's the previous message which appears.
Solve issue #57 
Solve issue #58