Cql2

[bitner]

• Bump version to 0.4.0
• Fixes syntax for IN, BETWEEN, ISNULL, and NOT in CQL 1 (fixes Support isNull in filters #69)
• Adds support for modifying settings through pgstac_settings table and by passing in 'conf' object in search json to support AWS RDS where custom user configuration settings are not allowed and changing settings on the fly for a given query.
• Adds support for CQL2-JSON (fixes Support for CQL2  #67)
  • Adds tests for all examples in https://github.com/radiantearth/stac-api-spec/blob/f5da775080ff3ff46d454c2888b6e796ee956faf/fragments/filter/README.md
  • filter-lang parameter controls which dialect of CQL to use
    • Adds 'default-filter-lang' setting to control what dialect to use when 'filter-lang' is not present
    • old style stac 'query' object and top level ids, collections, datetime, bbox, and intersects parameters are only available with cql-json

[mmcfarland]

Looks good, @bitner. I had a question about case insensitive 'LIKE' queries and suggested a test for it and the BETWEEN that was fixed in this PR.