This allows for cleaner separation between core and rosterview, making it
easier to remove that plugin for more stripped down deployments.

Similar to how backbone.js does it.

instead of having the ControlBoxView do it. This provides for cleaner
separation between the two plugins.

So that we can also fetch the roster also without the controlbox and rosterview.

When it's not possible to reconnect due to password no longer being cached,
render the login form.

Fixed a bug whereby after one failed reconnection event, reconnection becomes
impossible (due to 'connection' state of the controlbox).

Fall back to working version.

This allows for better desktop notification messages.
Also improved the wording for some of the feedback messages.

after a dropped connection.

- Add new configuration setting messages_storage
- Hardcode the storage for roster contacts and chatroom occupants to `sessionStorage`.

and drop the reconnection timeout to 3 seconds (from 5).

- Added the ability to reconnect to more disconnection causes.
- Make sure the roster is fetched again when reconnecting.

Send a <paused/> notification after 10 seconds, instead of 20.
Auto-remove a typing notification in the chat box after 20 secs instead of 10.

This is to avoid situations where the status notification gets
auto-removed while the typer keeps on typing without long enough breaks in
between for <pause/> states, thereby causing the recipient to not be aware that
they're still typing.

Problem was a race condition between hide and show methods.
Solution was to not hide the chat box during the initialize method.

For each user we keep a list of currently online resources. These resources
were taken from both presence and message stanzas.

Receiving a message doesn't however indicate that the user is online,
especially in the case of archived messages.

This also abused the semantics of messages, which are meant to indicate
user presence.

- Send chat state notifications with type groupchat for MUC.
- Don't show own chat state notifications if received from the server.