Changes

** Still, a change in wpkg.js is needed: wpkg.js needs to end with exit code 3010 - WPKG Client will reboot in that case.

** We don't wan't to reboot indefinitely if system administrator made an error - WPKG Client will reboot the machine only five times in a row; if wpkg.js still ends with exit code 3010, we won't reboot for the sixth time. To reset the counter, wpkg.js needs to exit with exit code different than 3010.

* WPKG service can be now disabled when everything is done (switch available in GUI).

* Settings can be imported from GUI and from command line.