Do not restrict broadcast address

[acollign]

We currently have a fixed list of broadcast address (BA) [0]. We already got two feedback asking for a way to manually change this address.

Our first thought was to restrict the broadcast addresses according to the ArtNet spec but it looks like there is more than one use case where you need to use another BA.

[0] https://github.com/Eliosoft/elios/blob/master/src/main/java/net/eliosoft/elios/gui/models/RemoteModel.java#L99