Updated README (facebook#1931)

* adding comment on windows support of nvm

* adding tree structure for intial project output

* applying feedback from this thread create-react-app/pull/1931

Author: shaunwallace

README.md

@@ -40,7 +40,7 @@ Install it once globally:
 npm install -g create-react-app
 ```
 
-**You’ll need to have Node >= 6 on your machine**. You can use [nvm](https://github.com/creationix/nvm#usage) to easily switch Node versions between different projects.
+**You’ll need to have Node >= 6 on your machine**. You can use [nvm](https://github.com/creationix/nvm#installation) to easily switch Node versions between different projects.
 
 **This tool doesn’t assume a Node backend**. The Node installation is only required for Create React App itself.
 
@@ -57,23 +57,23 @@ It will create a directory called `my-app` inside the current folder.<br>
 Inside that directory, it will generate the initial project structure and install the transitive dependencies:
 
 ```
-my-app/
-  README.md
-  node_modules/
-  package.json
-  .gitignore
-  public/
-    favicon.ico
-    index.html
-    manifest.json
-  src/
-    App.css
-    App.js
-    App.test.js
-    index.css
-    index.js
-    logo.svg
-    registerServiceWorker.js
+my-app
+├── README.md
+├── node_modules
+├── package.json
+├── .gitignore
+├── public
+│   └── favicon.ico
+│   └── index.html
+│   └── manifest.json
+└── src
+    └── App.css
+    └── App.js
+    └── App.test.js
+    └── index.css
+    └── index.js
+    └── logo.svg
+    └── registerServiceWorker.js
 ```
 
 No configuration or complicated folder structures, just the files you need to build your app.<br>