Reverse Link Indication - V lights up C

[cyberus111]

With the new cargo system requiring even more slaved blocks its getting a bit weird trying to remember which slaved blocks go to what master.

So .. it would be nice if we could V on a slaved block (any not just cargo if possible) and have the master block light up, having all the associated slaved blocks also light up would be a bonus but not a biggie if to much hassle to accomplish.