Otherwise compatibility with Conversations is broken.
Unfortunately this means that OMEMO won't work on Edge, because it
for some reason requires the additionalData.

References:
* https://github.com/conversejs/converse.js/issues/1187#issuecomment-426276243
* https://stackoverflow.com/questions/42933162/web-crypto-api-using-microsoft-edge-38-14393-0-0/42950731

Fixes #1187

Currently translated at 99.7% (338 of 339 strings)

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

Currently translated at 65.4% (222 of 339 strings)

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

Currently translated at 25.6% (87 of 339 strings)

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

Currently translated at 12.0% (41 of 339 strings)

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

Currently translated at 97.6% (331 of 339 strings)

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

Currently translated at 82.5% (280 of 339 strings)

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

Currently translated at 84.6% (287 of 339 strings)

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

Also udpate markup to not use `<source>`.

updates #1189

updates #1220

Fixes #1220

* Add support for webm video and m4a audio media files
* updated CHANGES.md

They're no longer needed since we're using webpack

Silently set status when it comes from a presence stanza

Otherwise the private chatbox header doesn't show in Firefox