Merge pull request #1 from Keksike/rnpm-to-react-native-in-readme

Switch from using rnpm to react-native cli in setup guide

README.md

 ## General Usage
 ```
 npm install --save react-native-permissions
-rnpm link
+react-native link
 ```
 
 Add permissions to manifest for android and info.plist for ios (xcode >=8). See notes below for more details.
 
 ````
 npm install --save react-native-permissions
-rnpm link
+react-native link
 ````
 
-### Or manualy linking
+### Or manually linking
 
 #### iOS
 * Run open node_modules/react-native-permissions