Otherwise we get an empty collection of features (due to features being
queried for a non-existent MUC)

No code relies on this currently, but it's seems the right thing to do

Also, handle the error in `getRoomFeatures`

As a namespacing mechanism to avoid clashes.
Fixes bug where two chats are shown as currently being active in the rooms list.

Causes problems with some versions of Ejabberd which use a different id.
Will be fixed in upcoming versions.

Currently translated at 99.7% (368 of 369 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/cs/

Currently translated at 100.0% (369 of 369 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/de/

Currently translated at 100.0% (369 of 369 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/gl/

Currently translated at 100.0% (369 of 369 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/es/

Currently translated at 72.1% (266 of 369 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/nb_NO/

Currently translated at 100.0% (369 of 369 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/fr/

The user manual is now here: http://github.com/conversejs/user-manual

Otherwise Converse will try to fetch the devices again and again upon
page refresh.

The devicelists are not stored in session storage, so we end up with
fetching all the devices per stored devicelist with every new browser
session.