3.3 upgrade routine

[nacin]

We need to remove a few usermeta keys on upgrade: show_admin_bar_admin and plugins_last_view.

While both were stored as global meta, they were fetched with get_user_option(), which means we could consider running a query looking for all table prefixes as well. Though, that's a bit rough on giant usermeta tables, so we could always stick to the basic keys.

[nacin]

In [18812]:

Remove remnants of show_admin_bar_admin. see #18811, see #18197.

[ryan]

Looks good.

[nacin]

In [19061]:

Introduce upgrade_330() to clear usermeta keys show_admin_bar_admin and plugins_last_view. fixes #18811.

[nacin]

In [19062]:

Merge upgrade_old_widgets_order_array() into upgrade_330(). see #18811, see #18821.