title: Titanium Android file.read() returns null for external media from intent
body: <p>When I invoke a gallery intent, I get the file ok, but trying to convert that file to a <code>blob</code> with <code>read()</code> gives null:</p>
  
  <p><strong>Q) How can i get the blob of this file?</strong></p>
  
  <p>Code:</p>
  
  <pre><code>    var intent = Ti.Android.createIntent({ action : Ti.Android.ACTION_PICK, type : "image/*" });            
      intent.addCategory(Ti.Android.CATEGORY_DEFAULT);
      win.getActivity().startActivityForResult(intent, function(e) { 
          if (e.error) { 
              alert(e.error);
          } 
          else {
              if (e.resultCode === Titanium.Android.RESULT_OK) {                  
                  var file = Ti.Filesystem.getFile(e.intent.data);
  
                  console.log('intentdata: ' + e.intent.data);
                  console.log('file: ' + JSON.stringify(file));
                  console.log('file read result: ' + JSON.stringify(file.read()));
              } 
          }
      }); 
  </code></pre>
  
  <p>Produces:</p>
  
  <pre><code>I/TiAPI   ( 2897):  intentdata: content://media/external/images/media/59
  I/TiAPI   ( 2897):  file: {"readonly":true,"bubbleParent":true,"writable":false,"directoryListing":null,"symbolicLink":false,"h
  idden":false,"nativePath":"content://media/external/images/media/59","executable":false,"size":0,"name":"butterfly2_large1.jpg"
  ,"parent":null}
  I/TiAPI   ( 2897):  file read result: null
  </code></pre>