Revert "Remove all the canvas stuff (will be use later)"

This reverts commit a6d92c0ae5a1d08c9cd493f1652dfec521a0e3c7.

	new file:   public/javascripts/canvas/canvas.js
	new file:   public/javascripts/canvas/map.js
	new file:   public/javascripts/canvas/tileset.js
	new file:   public/javascripts/tools/xhr.js
	new file:   public/javascripts/vendors/excanvas.compiled.js
	new file:   public/maps/map.json
	new file:   public/tilesets/chemin.png
	new file:   public/tilesets/tile.png
	modified:   views/game/index.jade
	modified:   views/layout.jade
	modified:   public/stylesheets/style.css