[Interface] Improvements of responsive design

[Anicky]

The canvas is responsive but only for the width. If the screen has a small height, the canvas is not complete on the screen.

Some tests :

var canvasMaxHeight = $(window).innerHeight() - 95;
var canvasMaxWidth = $('.panel-game').innerWidth();

var canvasSize = Math.min(canvasMaxHeight, canvasMaxWidth) + "px";

$("#canvas").attr('width', canvasSize).attr('height', canvasSize);