Also update changelog and fix some linting errors.

Fixes #360

Adding 'rooms' API

fixes #364

updates #359

Fix a timeout bug in chat state notifications

This caused a bug whereby a chat box would open only on chat state
notifications.

Also refactored the chats.open and chats.get methods so that they now reuse the
same map function and so that chats.get can now return any chat box and not
just already open ones.

Updated the tests to properly test this and updated the docs.

Fix the known bug where a state notification reopens a chat box

Fix the ChatRoomOccupants storage id

Fix the plugin extend function

Add tests for contacts.add API method and make it a bit more compact.
Add entry in changelog.

update #354

contacts.add API to register contacts

- Basic test if the given jid contains @
- use jid as name if undefined

when using prebind and keepalive together.

You don't see visitors without hovering the specific user. So you would have to check everyone by yourself. This highlights them grey. (You're also marked as visitor when you're muted)

Fixes build and test errors due to files having been moved around.
Fixes #351

specified.

fixes #330
updates #333

* The JID is only required when using keepalive with prebind.
* Provide a logout API method.

fixes #341

Hide 'Server' Label when hiding server input