Introduce info mechanism

We expose browser information as shadow tiddlers so that wiki
applications can adapt to available features.

core/modules/startup/info.js

@@ -0,0 +1,48 @@
+/*\
+title: $:/core/modules/startup/info.js
+type: application/javascript
+module-type: startup
+
+Initialise $:/info tiddlers via $:/temp/info-plugin pseudo-plugin
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+// Export name and synchronous status
+exports.name = "info";
+exports.before = ["startup"];
+exports.after = ["load-modules"];
+exports.synchronous = true;
+
+exports.startup = function() {
+	// Collect up the info tiddlers
+	var infoTiddlerFields = {};
+	// Give each info module a chance to fill in as many info tiddlers as they want
+	$tw.modules.forEachModuleOfType("info",function(title,moduleExports) {
+		if(moduleExports && moduleExports.getInfoTiddlerFields) {
+			var tiddlerFieldsArray = moduleExports.getInfoTiddlerFields(infoTiddlerFields);
+			$tw.utils.each(tiddlerFieldsArray,function(fields) {
+				if(fields) {
+					infoTiddlerFields[fields.title] = fields;
+				}
+			});
+		}
+	});
+	// Bake the info tiddlers into a plugin
+	var fields = {
+		title: "$:/temp/info-plugin",
+		type: "application/json",
+		"plugin-type": "info",
+		text: JSON.stringify({tiddlers: infoTiddlerFields},null,$tw.config.preferences.jsonSpaces)
+	};
+	$tw.wiki.addTiddler(new $tw.Tiddler(fields));
+	$tw.wiki.readPluginInfo();
+	$tw.wiki.registerPluginTiddlers("info");
+	$tw.wiki.unpackPluginTiddlers();
+};
+
+})();