0.5.3

What's Changed

• Fix resolve_column_path rejecting bare names that are both a flat column and a relationship
• Add README cookbook examples for backlinks
• Fix Postgres 500 on boolean flat-column literals (e.g. private is False)
• Add len(path) -- array-length comparisons over an intra-record JSON array
• Unify any()/len() with exists()/count() -- one dispatch, two keyword generations
• Add Person.child_refs -- a self-linked collection, closing the "adopted" gap
• Refresh docs to lead with any()/len(), the canonical spellings
• Add end-to-end test for backlinks comprehension sugar
• Fix comprehension sugar to desugar into any()/len(), not exists()/count()
• Lock in more any()/len() comprehension equivalences as regression tests
• Reject a relationship hop before a collection name consistently

Full Changelog: 0.5.0...0.5.3