Application Update: Update application files

This class can be used to update application files retrieved from a remote server.

It reads the list of application files to update from the remote server. Different sets of files may be available for different application versions.

The class can retrieve the files from the remote server and update the file's copys in the local server. It displays the progress of the updating after each file is transferred.

The class also check whether the local files are writable before updating them.