refactor(readme): improve installation instructions

README.md

@@ -8,13 +8,17 @@ This is the base template for Ionic starter apps.
 Install the latest Ionic CLI:
 
 ```bash
-$ npm install -g ionic
+$ npm install -g ionic cordova
 ```
+:memo: *Note: For a global install of `-g ionic`, OSX/Linux users may need to prefix
+the command with `sudo` or can setup [proper file permissions on OSX for
+npm](https://www.johnpapa.net/how-to-use-npm-global-without-sudo-on-osx/) to
+install without `sudo`.*
 
 Then run:
 
 ```bash
 $ ionic start myApp
 ```
 
-More info on this can be found on the Ionic [Getting Started](http://ionicframework.com/docs/v2/getting-started/) page.
+More info on this can be found on the Ionic [Getting Started](https://ionicframework.com/docs/v2/getting-started/) page.