message: Added partial encoding to a url to demonstrate proper handling of spaces in urls.
diff: <html lang="en">
  <head>
  <meta charset="UTF-8">
  - <link rel="import" href="imports/folder with spaces/import.html">
  + <!-- URLs should have unencoded spaces encoded to %20 -->
  + <link rel="import" href="imports/folder%20with spaces/import.html">
  <title>Sample Build</title>
  </head>
  <body>
  