Updated instructions for creating an app.

Janscas pointed out a better solution in O365#361 and O365#317. I've added a
sentence to the instructions to provide that extra bit of guidance.

Author: Toben Archer

README.md

@@ -156,7 +156,7 @@ This section is explained using Microsoft Graph Protocol, almost the same applie
     1. Login at [Azure Portal (App Registrations)](https://portal.azure.com/#blade/Microsoft_AAD_RegisteredApps/ApplicationsListBlade)
     1. Create an app. Set a name.
     1. In Supported account types choose "Accounts in any organizational directory and personal Microsoft accounts (e.g. Skype, Xbox, Outlook.com)", if you are using a personal account.
-    1. Set the redirect uri (Web) to: `https://login.microsoftonline.com/common/oauth2/nativeclient` and click register. This is the default redirect uri used by this library, but you can use any other if you want.
+    1. Set the redirect uri (Web) to: `https://login.microsoftonline.com/common/oauth2/nativeclient` and click register. This needs to be inserted into the "Redirect URI" text box as simply checking the check box next to this link seems to be insufficent. This is the default redirect uri used by this library, but you can use any other if you want. 
     1. Write down the Application (client) ID. You will need this value.
     1. Under "Certificates & secrets", generate a new client secret. Set the expiration preferably to never. Write down the value of the client secret created now. It will be hidden later on.
     1. Under Api Permissions: