v4.0.0

If you are upgrading: please see UPGRADING.md.

Changed

• Upgrade abstract-leveldown from ^5.0.0 to ^6.0.2 (#61) (@vweevers)
• Upgrade encoding-down from ^5.0.3 to ^6.0.1 (#61) (@vweevers)
• Upgrade levelup from ^3.0.1 to ^4.0.1 (#61) (@vweevers)
• Avoid unnecessary copy of batch operations (#61) (@vweevers)
• Invoke abstract tests from single function (#61) (@vweevers)
• Add mandatory db argument to abstract iterator (#61) (@vweevers)
• Upgrade memdown devDependency from ^3.0.0 to ^4.0.0 (#61) (@vweevers)
• Upgrade nyc devDependency from ^12.0.2 to ^13.3.0 (#61) (@vweevers)
• Upgrade standard devDependency from ^11.0.1 to ^12.0.1 (#61) (@vweevers)
• Apply common project tweaks (#58, #59) (@vweevers)

Added

• Test that errors from open() and iterators bubble up (#61) (@vweevers)
• Test without a user-provided levelup layer (#61) (@vweevers)
• Gitignore coverage directory (#61) (@vweevers)

Removed

• Remove obsolete _batch() checks (#61) (@vweevers)
• Remove dummy location from abstract-leveldown constructor call (#61) (@vweevers)

Fixed

• Serialize non-buffer keys to strings (#61) (@vweevers)