Dramaturg: Show the title or the URL instead of the domain name in the tab switcher

[mardukbp]

When several tabs belonging to the same web app are open the tab switcher makes it hard to switch to the correct tab, since the domain name is used as tab title:

Moreover, when a local file is open, the tab switcher shows an empty entry:

It would be more user friendly to show the <title> and if it is not set, show the URL of the tab.