mod_cloud_notify: Identify (and immediately push) urgent stanzas, e.g. calls This covers the following things: - A session that appears online, but has a broken TCP connection - Clients such as Siskin and Snikket iOS that require a push for calls to work It allows the stanza to be pushed immediately instead of waiting for the session to hibernate or an ack to timeout. It shouldn't break any existing cases.

# Introduction

This module sends a [version query][xep0092] to clients when they
connect, and logs the response, allowing statistics of client usage to
be recorded.

Note that since this is per connection, there will be a bias towards
mobile clients on bad connections.

## Example

    info    Running Running Swift version 4.0