New version with CRC32 checking

 Added CRC32 checking to the update procedure.
 Added support for the new Beta Demo folder on the FTP. All beta files are still saved to the selected beta folder.
 Users are now prompted to download the dat files when a prefs file is loaded and no data has been downloaded.
 All download files are size checked against the dat files and removed it they are wrong.
 HTTP download errors are logged in a file called error_log.txt.
 You can now toggle the file tree in the download preview.
 Downloads are a tiny bit slower as the files are size and crc checked once received.
 You can now save the download list as a text file.
 Fixed status bar spacing.
 Changing prefs files will prompt for clearing the database and will rescan the WHDLoad folders.
 Save Prefs button is now active all the time.
 The file list now shows any errors in your files by highlighting them with red for missing and blue for bad CRC32.
 Moved all donate links to a new window.