Return an object from access_log module

This allows adding more methods later.

app.js

@@ -5,7 +5,7 @@ var peliasConfig = require( 'pelias-config' ).generate().api;
 
 
 if( peliasConfig.accessLog ){
-  app.use( require( './middleware/access_log' )( peliasConfig.accessLog ) );
+  app.use( require( './middleware/access_log' ).createAccessLogger( peliasConfig.accessLog ) );
 }
 
 /** ----------------------- pre-processing-middleware ----------------------- **/

middleware/access_log.js

@@ -17,4 +17,6 @@ function createAccessLogger( logFormat ){
   });
 }
 
-module.exports = createAccessLogger;
+module.exports = {
+  createAccessLogger: createAccessLogger
+};