v3.0.5 -> v3.1.0
Rewrites caching:
- Trolley no longer caches results by default, cleans up Trolley.
- Completely rewrites CachedSearcher to implement Searcher interface
- Caching is now optional by wrapping any searcher instance
- Caching is now time-based and done per DICOM object
- Adds query caching (previously only get_study_for_id)
Makes reasoning about DICOM levels (study/series/instance) easier:
- Adds numeric value and comparison to DICOMObjectLevels
- Introduces DICOMObject.contained_references()
- Merges to_series_level_refs, to_instance_refs into to_refs(level)