Replace the recursive depth-first search of a wire network with an
iterative breadth-first search, primarily to reduce memory footprint and
eliminate the possibility of stack overflow.
Digilines is probably used by most people in its entirety.
I've retained the ability to disable inventory, rtc, lightsensor and
LCD by the minetest settings "diglines_enable_rtc" etc.. If set to
"false", these components will not be loaded. It is assumed by default
that these are enabled.
In the conversion the digilines_lcd:lcd node was renamed to
digilines:lcd (same for all the other nodes). To retain backwards
compatibility I've provided aliases for each of these nodes.
