The download file name & path can be changed now (#23)

solution of issue #12

installing.html

@@ -23,7 +23,7 @@
  <div class="panel-body" id="progress">
  </div>
  <div class="panel-footer">
- <a href="#" id="download-link">
+ <a href="path/to/file" download="renamed.txt" id="download-link">
  <div class="download-button" id="download-button">
  Waiting for the iso file. Your download link will be here.
  </div>