Update source and dependency to work with TypeScript 2.7. Closes #81

The commit brings compatibility with new features introduced in TypeScript 2.7.
The one with most impact on this project is ES6/ECMAScript module compatibility layer
added in 2.7 enabled in tsconfig.json for this project.
This allowed to rewrite source files to use shorted, better imports everywhere and
also use default exports.

To make project more aligned with updated TypeScript all the NPM depenendencies has been
updated making sure that everything works as expected and tests pass.

Thanks for the project!

Thanks!

src/server.ts

@@ -1,6 +1,6 @@
-import * as errorHandler from "errorhandler";
+import errorHandler from "errorhandler";
 
-const app = require("./app");
+import app from "./app";
 
 /**
  * Error Handler. Provides full stack - remove for production
@@ -11,8 +11,12 @@ app.use(errorHandler());
  * Start Express server.
  */
 const server = app.listen(app.get("port"), () => {
-  console.log(("  App is running at http://localhost:%d in %s mode"), app.get("port"), app.get("env"));
+  console.log(
+    "  App is running at http://localhost:%d in %s mode",
+    app.get("port"),
+    app.get("env")
+  );
   console.log("  Press CTRL-C to stop\n");
 });
 
-export = server;
+export default server;