Getting Started Clarifications and Example Code File (#904)

* added URI link to README getting started

* revised comment

* added alternate module installation instruction

* installation troubleshooting comment

* scope clarification comment

* added playlist_add_items.py to examples folder

* reformatted changelog edits

* Relocated added contributions to added section in Changelog

* removed unnecessary library installation instruction

* Clarified alternative installation instruction

README.md

@@ -14,6 +14,12 @@ Spotipy's full documentation is online at [Spotipy Documentation](http://spotipy
 pip install spotipy
 ```
 
+alternatively, for Windows users 
+
+```bash
+py -m pip install spotipy
+```
+
 or upgrade
 
 ```bash
@@ -43,6 +49,8 @@ for idx, track in enumerate(results['tracks']['items']):
 
 ### With user authentication
 
+A redirect URI must be added to your application at [My Dashboard](https://developer.spotify.com/dashboard/applications) to access user authenticated features.
+
 ```python
 import spotipy
 from spotipy.oauth2 import SpotifyOAuth