Merge pull request #221 from d-hat/CVE-2020-35381

Attempt to fix #219 and introduce a test.  The only error that can easily be returned in this case is `KeyPathNotFoundError`, which is reasonable if you squint (a malformed key can not be found).

Note I'm far from fluent in golang so this should be reviewed with some care 😄

Merge pull request #196 from AllenX2018/fix-issue-107

improve Set performance as #issue107 descripes

Merge pull request #197 from kcasctiv/fix-get-infinite-loop

Fix infinite loop in Get