pep8 blank lines fixes

flake8 --select W391,E302,E301,E304

autopep8 can't fix W391 even though it claims it can.
Fixed using a simple custom script.

weboob/tools/application/formatters/json.py

@@ -47,6 +47,7 @@ class JsonFormatter(IFormatter):
     """
     Formats the whole list as a single JSON list object.
     """
+
     def __init__(self):
         IFormatter.__init__(self)
         self.queue = []
@@ -66,9 +67,11 @@ class JsonLineFormatter(IFormatter):
     Formats the list as received, with a JSON object per line.
     The advantage is that it can be streamed.
     """
+
     def format_dict(self, item):
         self.output(json.dumps(item, cls=Encoder))
 
+
 def test():
     from .iformatter import formatter_test_output as fmt
     assert fmt(JsonFormatter, {'foo': 'bar'}) == '[{"foo": "bar"}]\n'