Implements a ping listener from XEP-0199 XMPP ping.
In the future, we can send an XMPP ping to the server to check for the state
of the connection.
/**
* This package contains the MemorizingTrustManager library made by Georg.
* It is a "plugin" for Android Java to allow asking the user about SSL certificates
* https://github.com/ge0rg/MemorizingTrustManager
*/
package de.duenndns.ssl;