title: Cordova/Phonegap File plugin searching file, confused about documentation
body: <p>I'm confused about the file plugin for cordova, this is my code :</p>
  
  <pre><code>function checkIfFileExists(path){
          window.requestFileSystem(LocalFileSystem.PERSISTENT, 10*1024*1024, function(fileSystem){
              fileSystem.root.getFile(path, { create: false }, fileExists, fileDoesNotExist);
          }, getFSFail);
  }
  
  
  checkIfFileExists("Framaroot-1.6.1.apk");
  }
  </code></pre>
  
  <p>First problem : If i replace "root" by "sdcard" (like the doc <a href="https://github.com/apache/cordova-plugin-file/blob/master/doc/index.md" rel="nofollow">https://github.com/apache/cordova-plugin-file/blob/master/doc/index.md</a> ), it's not working. When i read the doc, i understand that we can do that. I'm wrong ?</p>
  
  <p>Second problem : when i put "root", it's works, but root is not the sdcard, so why the function return me a true for search the Framaroot apk (he is in the root of sdcard) ?</p>
  
  <p>Third : If i want to search a particular file in destination that is know, what is the syntax for search the file test.txt in /sdcard/Android/data/com/domain.myapp/ directory ? I use "cdvfile" ?</p>