SPARK-2277 Add control over IBB file transfer via ClientControl (#698)
Since starting from Spark 3.0.0 IBB is disabled by default due to this bug https://igniterealtime.atlassian.net/browse/SPARK-2209 . But after updating the Smack library to version 4.4.X, I cannot reproduce this bug with the IBB setting. Perhaps some administrators may want to manage IBB settings via ClientControl plugin Openfire for their clients.
