Add GettingStarted tiddler for empty TiddlyWikis

core/messages/GettingStarted.tid

@@ -0,0 +1,11 @@
+title: $:/messages/GettingStarted
+type: text/vnd.tiddlywiki
+subtitle: Welcome to ~TiddlyWiki
+footer: <$button message="tw-close-tiddler" class="btn btn-primary">Close</$button>
+help: http://five.tiddlywiki.com/static/GettingStarted
+
+This ~TiddlyWiki is empty. 
+
+You can create and edit tiddlers, but before you use ~TiddlyWiki in earnest it is strongly advised that you verify that you can save and retrieve your changes.
+
+~TiddlyWiki5 is currently a preliminary alpha release. Visit http://five.tiddlywiki.com/ for the latest information on how to use it.

core/modules/startup.js

@@ -104,11 +104,15 @@ exports.startup = function() {
 		});
 		// If we're being viewed on a data: URI then give instructions for how to save
 		if(document.location.protocol === "data:") {
-			var event = document.createEvent("Event");
-			event.initEvent("tw-modal",true,true);
-			event.param = "$:/messages/SaveInstructions";
-			document.dispatchEvent(event);
-		} 
+			$tw.utils.dispatchCustomEvent(document,"tw-modal",{
+				param: "$:/messages/SaveInstructions"
+			});
+		} else if($tw.wiki.countTiddlers() === 0){
+			// Otherwise, if give instructions if this is an empty TiddlyWiki
+			$tw.utils.dispatchCustomEvent(document,"tw-modal",{
+				param: "$:/messages/GettingStarted"
+			});
+		}
 		// Display the PageTemplate
 		var templateTitle = "$:/templates/PageTemplate",
 			parser = $tw.wiki.parseTiddler(templateTitle),