bring back optional pictures to kiwi-locator
Morepork-locator: find moreporks by looking for tonal patterns

The canonical morepork call consists of two downward arching
syllables, with the second syllable usually being lower and fainter than
the first. Like this ⏜ ︵ (utf-8), but with more of a drop in tone at the
end of each syllable.

The morepork-locator distinguishes these calls by looking for pure tones
within the morepork frequency band, and comparing their timings to a
template.  It does quite well in noisy environments, but is not very good
at detecting lazy moreporks who hardly pronounce their second syllable.
Fiddling with the morepork-locator, trying log ratio errors

This doesn't really work much better.
Tragic and hopeless manipulation of morepork-locator from some weeks ago

This is going in just for the record. Don't look at it.
Script that estimates and stores the intensity of each call

The calls are stored as a series of JSON one-liners. If you imagine
the following all being on one line:

["AI137_BIRM_120203_052707-09+60.wav",
    [0.25, 1.0, 3.894248141223105],
    [4.55, 5.35, 4.376498257003673]]

you'll see it notes two calls in "AI137_BIRM_120203_052707-09+60.wav",
each with a start time, end time, and intensity score, respectively.

To calculate the intensity, the spectrogram power values in the
relevant band of frequencies (set via -L and -H command line
arguments) during the call are sorted and the 5th and 95th centiles
are taken. The score is the log ratio between the two.

In thwe above example, the first call (starting 0.25 seconds in with a
score around 3.9) is barely audible, and the second one is faint. This
suggests a threshold of about 4.0 might work well for moreporks.