docs: fixed examples of using "parse" (#149)

README.md

@@ -125,7 +125,7 @@ This is the simplest case. Get the script in whatever way you prefer and include
 <script src="//path/to/mpd-parser.min.js"></script>
 <script>
   var mpdParser = window['mpd-parser'];
-  var parsedManifest = mpdParser.parse(manifest, manifestUrl);
+  var parsedManifest = mpdParser.parse(manifest, { manifestUri });
 </script>
 ```
 
@@ -136,14 +136,14 @@ When using with Browserify, install mpd-parser via npm and `require` the parser
 ```js
 var mpdParser = require('mpd-parser');
 
-var parsedManifest = mpdParser.parse(manifest, manifestUrl);
+var parsedManifest = mpdParser.parse(manifest, { manifestUri });
 ```
 
 With ES6:
 ```js
 import { parse } from 'mpd-parser';
 
-const parsedManifest = parse(manifest, manifestUrl);
+const parsedManifest = parse(manifest, { manifestUri });
 ```
 
 ### RequireJS/AMD
@@ -152,7 +152,7 @@ When using with RequireJS (or another AMD library), get the script in whatever w
 
 ```js
 require(['mpd-parser'], function(mpdParser) {
-  var parsedManifest = mpdParser.parse(manifest, manifestUrl);
+  var parsedManifest = mpdParser.parse(manifest, { manifestUri });
 });
 ```