Fix case mismatch in behave step (#129)

Author: hudlow

features/steps/cli_binding.py

@@ -34,7 +34,7 @@
 from behave import *
 
 
-@given(u'JSON Document \'{json}\'')
+@given(u'JSON document \'{json}\'')
 def step_impl(context, json):
     context.data['json'].append(json)