Handle debug boolean complete properties
Minor UI tweaks to RPi node
Add "topic based fair queue" option to delay node
Reduce logging for exec node
(can be re-enabled by using node -v red.js ... )
Try to ensure TCP node closes server connections on redeploy
(to clean up properly - especially in case of port changes)

Closes Issue #454
Clone messages before any node.receive call
Node drag start threshold incorrectly calculated