test(async): Remove unused `testDone` args
fix(FileStub): Set 'parentName'
test(FileStub): Finish remaining skipped tests
fix(FileStub): Correct readdir payload after rename

- #renameSync: Remove old path from parent readdir
- #readdir: make() files listed in string path array
- #unlink: Only modify parent readdir if relative path exists
fix(fs stub): Stub exists*() manually

Rely on the file stub map instead of withArgs+returns because subsequent
return payloads don't have an effect.
fix(fs stub): Replace stubs with wrappers

- Ex. allow reassignment of readFile*() return payload for a given path.
- Ex. allow optional (default) fallback to real `fs` if stub does not
  exist.
fix(fs wrap): Copy stats during renameSync

- Finish skipped tests.
fix(FileStub): Set default size/blocks to 0

Set more intuitive defaults given that #buffer updates the size.

- Not sure how #buffer should calculate blocks. Will add later as/if
  needed.
fix(constructor): Update already-doubled logic
feat(fs wrap): Add unlink*() wrappers
feat(fs fallback): Optionally throw an Error
chore(pkg): Bump version