Connections to the IP interface are not cleared

[pellenbeck]

In the current version (Node-RED 1.3.5 and node-red-contrib-knx-easy 0.3.3) the existing connections to the KNX IP interface are not closed when redeploying flows. Thus, all possible connections of the interface are occupied relatively quickly and no further connection of the latest deployment is possible.

With older versions of Node-RED this problem do not exist.