* Update flake8 from 3.6.0 to 3.7.4
* Update mypy from 0.650 to 0.660
* Update pycodestyle from 2.4.0 to 2.5.0
* Update pyflakes from 2.0.0 to 2.1.0
* Update pytest from 4.0.2 to 4.2.0
* Update pytest-cov from 2.6.0 to 2.6.1
* fix test linting
* Properly set Config in create_model
Set the Config attribute in create_model, so it is found by the
MetaModel.
* Black formatting fixes
* Remove uneeded validator logic
* Use single quotes
* Add return value to inherit_validators
* Refactor inherit_validators
* Add HISTORY.rst entry
* Address feedback
* Extend existing validator test cases and remove field aliasing
* Add test cases for validators inherted from parent
* Make test case names consistent with where validators are configured
* Add detail create_model validator inheritance tests
* use type() in int validator to avoid returning a bool since bool is and instance of int
* add note to HISTORY.rst
* add tests & add username and PR # to HISTORY.rst
* use not ininstance(v, bool) to allow int subclassing
* Get rid of `track` in errors
* Move `display_as_type` func into utils module
* Get rid of error as `namedtuple`
* Renamed `Error.index` to `Error.loc`
* New way to get error type
* New way to get error message
* New errors format
* Renamed `flatten_errors` property to `flat_errors`
* `__slots__` for `Error` and `ValidationError`
* `loc` as `tuple`
* Tests
* Review fixes
* `flatten_errors` as generator