Function does not necessarily check for latest version. Also, it does not actually get the update, just the version, so rename function to 'getUpdateVersion' to match 'getCurrentVersion'. Similarly with 2 variable names.
* Use vcgencmd otp_dump to get the board-revision because the format
is predictable.
* Change the -f completion message to indicate that the update is
scheduled rather than complete.
* Add some notes to help about the update mechanism.
