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
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
discriminator: checking fields are inclusive. #1820
discriminator: add test cases when checking fields are inclusive. #1820
Merge branch 'fix-discriminator-find-with-fields-filter' of git://github.com/daemon1981/mongoose into 1819
bump mquery to 0.4.1
use mquery 0.4.1 methods for selected fields
updated; driver to 1.3.23

As a side-effect, mongodb no longer passes the stats as a third
argument to a mapReduce callback unless the verbose option is set. To
provide backwards-compatibility, we will set it unless it is explicitly
unset.

Conflicts:
	package.json
release 3.8.4