fix model.discriminator.querying tests dependencies and use async in dev dependencies to be more readable. #1820
fix hydrates correct models when finding with discriminators and fields selection set. #1820
fix discriminator model only finds documents of its type when fields selection set. #1820
test findOne discriminator model only finds a document of its type when fields selection set. #1820
make find and findOne discriminator fix identical. #1820
now working on 3.8.3-pre
Handles exceptions much better
Bump `mpromise` to 0.4.3

No new user facing features, and good code coverage.
Handles exceptions much better.
fixed; setting empty array with model.update

closes #1838
docs; fix url
release 3.8.3
fix issue #1834
now working on 3.8.4
fix discriminator find when param fields is an object. #1820
add tests on finding with discriminator and selection fields as object. #1820
fix discriminator find when select fields are exclusive. #1820
Reproduce issue 1846
Fix for #1846
Merge pull request #1837 from Empeeric/3.8.x

Bump `mpromise` to 0.4.3
Merge pull request #1839 from chetverikov/3.8.x

fix issue #1834