Introduce a table mapping notices to Twitter statuses. Initialize
this table at checkSchema() time. Save the mapping when we push
or pull statuses. Use the table to determine if a notice has a
Twitter equivalent.
default; can be re-added with setting:
addPlugin('TwitterBridge', array('adminImportControl' => true, ....));
Added a note on the label that it requires manual daemon setup. (Note that by default the admin panel won't be shown, so it's no biggie to be hiding this for now.)