Merge pull request #127 from thalelinh/master

Fixed trusty example calling `then` instead of `fetch`

README.md

 RNFetchBlob.config({
   trusty : true
 })
-.then('GET', 'https://mysite.com')
+.fetch('GET', 'https://mysite.com')
 .then((resp) => {
   // ...
 })