IE9 limitation workaround: Post windows messages as JSON

IE9 doesn't support posting objects.
Avoid quirks mode: add doctype

Also change test site id; I had to install a new database and generate a
new site, because the IE9 VM prevents me from running my PostgreSQL VM
simultaneously.
Add jQuery browser plugin, since $.browser gone in jQuery 1.9.
Fix Utterscroll in IE9: Don't check `buttons === 0`, it's always true.
Make IE save cookies from <iframe>s: add dummy P3P header.
Merge branch 'topic-fix-ie-iframe-issues'.
Start implementing a login popup dialog

HTML and CSS seems to work, but logging in doesn't.
Break out Scala template for Weinre script.
Move scripts from client/page/ to client/login-popup/.
Fix CSS: avoid scrollbars in login dialog, show widget-overlay.
Change login popup submit button title.
Don't close login popup if clicks Escape.
Don't show annoying "You closed the login window" message.
Make login popup actually login, at least guest login

- Include missing dependencies
- Call window.opener...handleLoginResponse() from login popup
- Call close() earlier
Don't ask about email notifications of replies, assume users want them

Assume users want email notifications if they provide any email address.
Now I can remove lots of complicated code that doesn't play well with
<iframe>s: the code opens a modal dialog inside the iframe and asks
about email, but modal dialogs in iframes are kind of pointless.
Fix bug that prevents email notifications: upgrade debiki-dao-rdb

If no email notification preferences specified, the site id is not loaded
and that prevents sending email notifications to guests.
Remove logout and login confirmation dialogs

They don't play well with iframes.
Make Facebook login work in login popup

- Set window.location = url, don't call createLoginPopup
- Remove dependency debiki-login-popup.js
Merge branch 'topic-iframe-login-popup'.
Fix old compilation errors in test suite.