Adds support for "not like" and "in" query condition operators (fixes #90)

Adds support for `o: "not like"` (handled identically to `o: "like"`) in AVU query

Adds support for `o: "in"` in AVU query, in which case the `value` must be a 
JSON array rather than a string. For example:
`{attribute: "sample", value: ["HGDP5851426", "HGDP5851427"], o: "in"}`