More cleanup

src/filehandler/plugin.ts

@@ -28,8 +28,8 @@ import {
  * This is called automatically when the plugin is loaded.
  */
 export
-function resolve(container: Container): Promise<void> {
-  return container.resolve({
+function resolve(container: Container): void {
+  container.resolve({
     requires: [IServicesProvider, IFileOpener],
     create: (services, opener) => {
       let handler = new FileHandler(services.contentsManager);

src/notebook/plugin.ts

@@ -37,8 +37,8 @@ import './plugin.css';
  * This is called automatically when the plugin is loaded.
  */
 export
-function resolve(container: Container): Promise<void> {
-  return container.resolve({
+function resolve(container: Container): void {
+  container.resolve({
     requires: [IServicesProvider, IFileOpener],
     create: (services, opener) => {
       let handler = new NotebookFileHandler(services.contentsManager);

src/terminal/plugin.ts

@@ -22,8 +22,8 @@ import './plugin.css';
 
 
 export
-function resolve(container: Container): Promise<void> {
-  return container.resolve({
+function resolve(container: Container): void {
+  container.resolve({
     requires: [IAppShell, ICommandPalette, ICommandRegistry],
     create: (shell, palette, registry) => {
       let termCommandItem = {