[Windows] App Cert Kit tests not passing for UTF-8 file encoding

[ghost]

Error messages:

<TEST INDEX="49" NAME="UTF-8 file encoding" DESCRIPTION="Packages containing an HTML5 Windows Store app must have correct file encoding." EXECUTIONTIME="00h:00m:02s.29ms">
  <RESULT><![CDATA[FAIL]]></RESULT>
  <MESSAGES>
    <MESSAGE TEXT="File D:\Projects\MyApps\WATDocs\platforms\windows\build\windows\debug\anycpu\AppX\www\js\wrapper.js is not properly UTF-8 encoded. Re-save the file as UTF-8 (including Byte Order Mark)." />
    <MESSAGE TEXT="File D:\Projects\MyApps\WATDocs\platforms\windows\build\windows\debug\anycpu\AppX\www\wrapper.html is not properly UTF-8 encoded. Re-save the file as UTF-8 (including Byte Order Mark)." />
    <MESSAGE TEXT="File D:\Projects\MyApps\WATDocs\platforms\windows\build\windows\debug\anycpu\AppX\www\css\wrapper.css is not properly UTF-8 encoded. Re-save the file as UTF-8 (including Byte Order Mark)." />
  </MESSAGES>
</TEST>