Add Styled.template_hash.
Don't render cache PrintableButtons subclasses.

This includes BanButtons, LinkButtons, CommentButtons, and
MessageButtons. These buttons templates shouldn't be cached on their
own because they'll be cached as part of the Printable template
(Link, Comment, or Message) that they're embedded in.
Unsafe UserText link_childs.
Don't render cache UserText.

They are usually embedded in a Printable and will get cached
as part of that entire object.
Add VModhashIfLoggedIn validator.
Fix if statements in prefoptions.html.
Add a notice when localized default subreddits are used.

Also let users opt-out and see the global default subreddits.
_ThingSavesBySubreddit: Get more saved values.