Include pseudo signals in the trains item/fluid count condition

[Impatient]

TL;DR

Include a pseudo signal in the trains item/fluid count condition to allow testing if anything of any type is in the train.

Why ?

This would allow to easily test if a train is not empty (but also not full) if it has items/(fluids) of different and unknown types loaded. I write "easily" because it also is possible to do this with a combinator and the train station. I think though that for consitency reasons the pseudo signal should be available in the trains item/fluid count condition as well.