Make v2 URLs work
Update default to v2 URL, remove debug code
Addresses the following issues:

- The query for matching classes against a known vulnerable artifiact
  was not working correctly.

- Metadata was not being correctly extracted from the MANIFEST.MF file.

- Comparing by a crude entire file hash was restored, allows for quick checks.

- Removed tolerance as no longer required

- Switched to using H2 instead of Apache Derby.