Fixing small bugs

Fixed a few small bugs, but a few more to go.  Here's what I'm doing:
* Run `generate_subtitle_map` - seems to output reasonably.  Cool!
* Run `cache_subtitles --language=gu` - starts with 444 subtitles, gets 97
* Run `cache_subtitles --language=za` - starts with 3 subtitles, gets 1.

Expect:
* When I run my distributed server, it will have two options--gu (97) and za(1)

Current behavior:
* One subtitle available: gu (96).

One problem might that you're overwriting your subtitle_counts.json and listedlanguages.json without reading them.  That would explain why only one subtitle count is in there.  However, I'm not sure why the number is off by one.

Note that I switched the 'open' mode from 'wb' to 'ab' - that's wrong. please change back.

Please work on this scenario until you've got it!

P.S. what is the use of listedlanguages.json?