. (kfsone) "buy" command:
- now accepts multiple arguments (e.g. explosives,clothing),
- new "--one-stop" (-1) option only shows stations that carry the full list,
- mixing ships and items is not allowed,
e.g.
trade.py buy food clothing fish
trade.py buy --near achenar fish,food,grain --one-stop
trade.py buy --near achenar --ly 100 type6,type7 --one-stop
trade.py buy --near achenar --ly 100 type6,type7 -1