[moc] NER H Class 0-4-0t (redone)

I actually did this locomotive like a year ago (I've included a picture of the old version in yellow), but was never particularly happy with it. The original version had a 1-stud-thick rear cab wall, which made getting a minifigure in there awkward (and look silly). Additionally, while I could fit a circuit cube motor in the old version, I couldn't manage to squeeze the battery cube in there, too (at least not without compromising structural integrity). I spent like 4 hours reworking the...