consistently use inline=False as default in capa inputtypes

common/lib/capa/capa/inputtypes.py

@@ -325,7 +325,7 @@ class OptionInput(InputTypeBase):
         Convert options to a convenient format.
         """
         return [Attribute('options', transform=cls.parse_options),
-                Attribute('inline', '')]
+                Attribute('inline', False)]
 
 registry.register(OptionInput)
 

common/lib/capa/capa/tests/test_inputtypes.py

@@ -55,7 +55,7 @@ class OptionInputTest(unittest.TestCase):
                     'options': [('Up', 'Up'), ('Down', 'Down')],
                     'status': 'answered',
                     'msg': '',
-                    'inline': '',
+                    'inline': False,
                     'id': 'sky_input'}
 
         self.assertEqual(context, expected)