Add action-createtiddler widget

Basically the same as sending a tm-new-tiddler message except that the
newly created tiddler is not added to the story.

core/modules/widgets/action-createtiddler.js

@@ -0,0 +1,81 @@
+/*\
+title: $:/core/modules/widgets/action-createtiddler.js
+type: application/javascript
+module-type: widget
+
+Action widget to create a new tiddler with a unique name and specified fields.
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+var Widget = require("$:/core/modules/widgets/widget.js").widget;
+
+var CreateTiddlerWidget = function(parseTreeNode,options) {
+	this.initialise(parseTreeNode,options);
+};
+
+/*
+Inherit from the base widget class
+*/
+CreateTiddlerWidget.prototype = new Widget();
+
+/*
+Render this widget into the DOM
+*/
+CreateTiddlerWidget.prototype.render = function(parent,nextSibling) {
+	this.computeAttributes();
+	this.execute();
+};
+
+/*
+Compute the internal state of the widget
+*/
+CreateTiddlerWidget.prototype.execute = function() {
+	this.actionBaseTitle = this.getAttribute("$basetitle");
+	this.actionSaveTitle = this.getAttribute("$savetitle");
+	this.actionTimestamp = this.getAttribute("$timestamp","yes") === "yes";
+};
+
+/*
+Refresh the widget by ensuring our attributes are up to date
+*/
+CreateTiddlerWidget.prototype.refresh = function(changedTiddlers) {
+	var changedAttributes = this.computeAttributes();
+	if($tw.utils.count(changedAttributes) > 0) {
+		this.refreshSelf();
+		return true;
+	}
+	return this.refreshChildren(changedTiddlers);
+};
+
+/*
+Invoke the action associated with this widget
+*/
+CreateTiddlerWidget.prototype.invokeAction = function(triggeringWidget,event) {
+	var title = this.wiki.generateNewTitle(this.actionBaseTitle),
+		fields = {},
+		creationFields,
+		modificationFields;
+	$tw.utils.each(this.attributes,function(attribute,name) {
+		if(name.charAt(0) !== "$") {
+			fields[name] = attribute;
+		}
+	});
+	if(this.actionTimestamp) {
+		creationFields = this.wiki.getCreationFields();
+		modificationFields = this.wiki.getModificationFields();
+	}
+	var tiddler = this.wiki.addTiddler(new $tw.Tiddler(creationFields,fields,modificationFields,{title: title}));
+	if(this.actionSaveTitle) {
+		this.wiki.setTextReference(this.actionSaveTitle,title,this.getVariable("currentTiddler"));
+	}
+	return true; // Action was invoked
+};
+
+exports["action-createtiddler"] = CreateTiddlerWidget;
+
+})();