- Increase z-index for chatbox flyouts so that they appear above the controlbox
- Also fix a margin offset bug for the controlbox (in smaller viewports)

Also move some other methods out of `converse-core` into the plugins
that use them.

- Always try to first get local cache before requesting the roster.
- Rename `roster_fetched` with `roster_cached`

Doesn't appear to be very useful. IIRC it was added as a workaround for
slow roster issues.

This was used for tests but is no longer necessary.

- Inform the user when fetching of bookmarks times out.
- Only set the cached flag if the user doesn't have bookmarks.

This is in anticipation of the localforage/IndexDB merge

They aren't used anymore.

Only XML is supported for now.

since we can't assume it's always available.

Fixes #1691

We need to set the assets path for CDN builds