Never update the local text while the user is typing

1. User types in the browser
2. The editor sends some text (like in #180)
3. The browser overrides whatever the user types with what the editor sends.

This is a mistake. If you're typing somewhere, that's the only version that matters. External messages should be ignored. I attempted to fix this with faa5a8d8ea744907b1f968b915c34f30e1dd96a7 but it caused #181.

This applies to both parts (browser or editor) but it's probably easier to avoid both issues in the browser:

- do not echo received text back to the editor (I think this is already done)
- ignore text from the editor while the field is focused