fix-#725: queryset delete() should return the number of deleted objects
Added PyPy3 to the build matrix.
Merge pull request #727 from DavidBord/fix-725

fix-#725: queryset delete() should return the number of deleted objects
Added landscape.io badge.
Added PyMongo 2.7.2 to the build matrix.
Merge pull request #728 from MongoEngine/topic/landscape-io

Added landscape.io badge
Update .travis.yml

Added coveralls coverage...