Fix td extension.

editor/extension.ts

@@ -19,8 +19,9 @@ namespace pxt.editor {
                     project.createProjectAsync({
                         filesOverride: { "main.blocks": "", "main.ts": "  " },
                         name: data.meta.name
-                        }).then(() => project.convertTouchDevelopToTypeScriptAsync(data.source))
-                        .then(text => this.textEditor.overrideFile(text))
+                    })
+                    .then(() => project.convertTouchDevelopToTypeScriptAsync(data.source))
+                    .then(text => project.overrideTypescriptFile(text))
             }]
         };
         return Promise.resolve<pxt.editor.ExtensionResult>(res);