Property for tab navigation

Added Engine.tabNavigation property. When true, it enables keyboard navigation to/from tabs. It is disabled on world and enabled some milliseconds after Path.onArrival(), so that when player returns s/he finds him/herself on Path tab instead of navigating.

script/world.js

@@ -823,6 +823,7 @@ var World = {
 					$('#outerSlider').animate({opacity:'1'}, 600, 'linear');
 					Button.cooldown($('#embarkButton'));
 					Engine.keyLock = false;
+					Engine.restoreNavigation();
 				}, 2000, true);
 			});
 		}
@@ -865,6 +866,7 @@ var World = {
 		$('#outerSlider').animate({left: '0px'}, 300);
 		Engine.activeModule = Path;
 		Path.onArrival();
+		Engine.restoreNavigation();
 	},
 	
 	leaveItAtHome: function(thing) {