[tompollard]

Summary

• Bump the version to 0.2.0. Since 0.1.6 this adds physionet.load() and physionet.fetch() (Load tables from PhysioNet through a local cache #190) and duplicate-file warnings in validation (Warn about duplicate files during validation #189), with ignore patterns applied the same way in every check.
• When PhysioNet cannot be reached and a file or its checksum list is not cached yet, load() and fetch() now raise a single ConnectionError naming the dataset and cache folder, instead of a long proxy or socket traceback.
• README: offline use needs one online load first; the source option, XDG_CACHE_HOME and per-server cache folders are described; the errors load() and fetch() raise are listed and added to Error Handling.

Verification

• pytest -q: 312 passed, 1 skipped.
• New tests cover the offline errors, including that a failed download leaves no partial files.
• Checked against physionet.org: an uncached load behind an unreachable proxy gives the new message; the README error examples raise the documented errors.