add extractor arg to filter for "key station only"

Programmes that air on a network of stations have an originating station-
a "key" station. e.g. for all night nippon the key station is ニッポン放送 (LFR)

radiko's new APIs include a key_station field.
I'd only seen such a field in the mobile-web site until now, so I
haven't been able do anything with it. But now the PC website's gotten
this "persons" API, so I can.

this arg is currently only useful for the new "persons" urls,
but i suspect it might become more useful as time goes on...

example usage:
you give the url for the host of a networked show,
the default will download from every station (probably not what you want)
but if you specify key-station-only, then you get just one download from
the originating station

i may add a "preference" argument at some point, for if you want it from
a specific non-key station, but not right now

0 files changed, 0 insertions, 0 deletions