install.sh :
	now change the owner of the directory EPFLCloudPrint to www-data on Linux and _www on Darwin (Mac OS X)
print.coffee
	Adding an error message when we are not login (Bad Credentials)
dropbox.php print.php remove_file.php upload_file.php :
	Adding if(!isset($_SESSION['username'])) such that if the username is not set we return an error_code
logout.php
	Simply unset the username such that next time you reload the webpage the server will ask you to login with Tequila