Long delay when exiting the add command

[dnarvaez]

When I run volo add in my project, the dependencies installation ends pretty quickly but then I see a > 1 minute delay before the command exits. Everything is apparently already done when it hangs, the okText in the volo script has been printed. The following patch seems to solves it but, knowing very little about promises, it doesn't feel like the right fix.

@@ -15,6 +15,7 @@ var args = [].splice.call(process.argv, 2);
     if (okText) {
         console.log(okText);
     }
+    process.exit(0);
 }, function (errText) {
     console.log('ERROR: ' + errText);
     process.exit(1);

My node version is v0.10.8, volo git master, debian jessy.