Improve round-trip

[jeremyrsellars]

Fixes #2. Fixes #3.

• Test more scenarios with generative tests via test.check.
• Fixes diff and patch when maps have nil or false as keys.
• Fixes support for sequences that change from one data structure to another.
• Fixes support for sequences which become empty.
• Add deps.edn for tools.deps git coordinates.
• Update dependencies and build targets.
• Proposes changing library to version 0.4.0.
• Support replacing a record with another record.

[jeremyrsellars]

My company has stored many months of diffs (version 0.3.3). I ran millions of them through to make sure the new 0.4.0 patch function could process the 0.3.3 diffs without exception.