Popups and modals will no longer try to restore a covered document title
and URL if they were opened without pushing a history entry.
When fragments are replaced without pushing a new history entry,
the document title will no longer be changed by default.
Breaking changes
The { url } option for up.destroy() has been renamed to { history } to be more
in line with up.replace().
Upgrading
If you're upgrading from an older Unpoly version you should load unpoly-migrate.js
to polyfill deprecated APIs.
Changes handled by unpoly-migrate.js are not considered breaking changes.
