added render() convenience method. Returns an EventEmitter if no callback was passed.

lib/less.js

@@ -7,7 +7,33 @@ var less = {
     version: [2, 0, 0],
     Parser: require('less/parser').Parser,
     importer: require('less/parser').importer,
-    tree: require('less/tree')
+    tree: require('less/tree'),
+    render: function (input, options, callback) {
+        options = options || {};
+
+        if (typeof(options) === 'function') {
+            callback = options, options = {};
+        }
+
+        var parser = new(this.Parser)(options),
+            ee;
+
+        if (callback) {
+            parser.parse(input, function (e, root) {
+                callback(e, root.toCSS());
+            });
+        } else {
+            ee = new(require('events').EventEmitter);
+
+            process.nextTick(function () {
+                parser.parse(input, function (e, root) {
+                    if (e) { ee.emit('error', e) }
+                    else   { ee.emit('success', root.toCSS()) }
+                });
+            });
+            return ee;
+        }
+    }
 };
 
 ['color',    'directive', 'operation',  'dimension',