Support queries where outputs are not 1:1 with inputs

[charles-dyfis-net]

Per #27. Implements a (slower) MultiOutputContainer that generates a JSON list of the query's results when given the active input, used when :multi true is set.

[dainiusjocas]

It turns out that this PR is not a "feature request" it is actually a bug fix 🥇

My original implementation assumed that PathOutput#emit is called only once per call to JsonQuery#apply which is not correct. This is clear when debugging your examples in #27.

[charles-dyfis-net]

Hmm; if that's the case it might call for changing the :multi false default, or at least documenting reliance on that default as deprecated and due to be changed in the next major release. I yield to your judgment on matters of balancing correctness and compatibility.

[dainiusjocas]

Hmm; if that's the case it might call for changing the :multi false default, or at least documenting reliance on that default as deprecated and due to be changed in the next major release. I yield to your judgment on matters of balancing correctness and compatibility.

For now, we definitely need to make :multi false the default. And then I'll add more test cases so that the default behaviour is compatible with jq.

[dainiusjocas]

The tricky bit is that JQ always returns a stream (0 or more) of json entities https://stackoverflow.com/a/69303619/1728133.

A helpful intro https://github.com/pkoppstein/jq/wiki/A-Stream-oriented-Introduction-to-jq

[charles-dyfis-net]

Indeed so. A more designed-to-purpose interface might return a seq, which would allow laziness as an implementation detail; as it is, though, returning an ArrayNode is returning a seqable, which this PR takes advantage of in the CLI implementation.