Format project with black (#467)

Format with line length 110 to match flake8

make black part of linting check

Update travis spec for updated black requirements

Add diff output for black on failure

update changelog

vcr/__init__.py

@@ -7,14 +7,16 @@ from .config import VCR
 try:  # Python 2.7+
     from logging import NullHandler
 except ImportError:
+
     class NullHandler(logging.Handler):
         def emit(self, record):
             pass
 
+
 if sys.version_info[0] == 2:
     warnings.warn(
         "Python 2.x support of vcrpy is deprecated and will be removed in an upcoming major release.",
-        DeprecationWarning
+        DeprecationWarning,
     )
 
 logging.getLogger(__name__).addHandler(NullHandler())