Upgrade from the command line

[pageer]

Now that we have a CLI entry point, we should allow upgrading blog wrappers/data from the command line. It's silly to require the user to upgrade each blog through the admin UI, especially if you're already on the server, e.g. to run a git pull. Proposed commands: php ./cli.php --upgrade to do everything or php ./cli.php --upgrade=myblog to upgrade just "myblog".

Note that we need to make sure that user accounts are handled properly for this, because we don't have a "current user" when running from the CLI.