[file-lister] Sending multiple messages overwrites previous output

[boisei0]

When using the file-lister node, the default multiple files as output will cause the input message to be used and overwritten for every time it outputs. This causes problems further in the flow, as the msgid stays the same everywhere.

This can be solved locally (very hacky) by adding a function node directly after the file-lister node to turn the incoming msg into a new msg with the same properties but is likely to break even further when Node-RED 1.0 is released. A better idea is to rather than edit the properties on the original message to create a new message for every node.send() call.