Site Settings page is a hot mess

[wonderboymusic]

I found out just how bad this page is when debugging an issue related to WPLANG. WPLANG is an option for a blog in your network (overrides WPLANG in wp-config.php), but if you delete the option on purpose or accidentally, there is no way of restoring it in the admin.

Site Settings just loads your options table and POSTs back to itself. The only reference to the original options map (the defaults) is in schema, which WP has zero access to outside of upgrade.

I have abstracted the default options and the default "fat" options into functions in ms.php. Also, when loading your Site Settings options - if a default option is missing, I display it in the admin so you can save it (it is populated with its default value).

I have also streamlined and condensed some code that was happening in and around populate_options()

populate_options() isn't just used for multisite — it's for the initial install, too.