lower testcase key

ate/runner.py

@@ -1,4 +1,4 @@
-from ate import exception, response
+from ate import exception, response, utils
 from ate.client import HttpSession
 from ate.context import Context
 
@@ -48,6 +48,9 @@ class Runner(object):
             }
         @param (str) context level, testcase or testset
         """
+        # convert keys in request headers to lowercase
+        config_dict = utils.lower_dict_key(config_dict)
+
         self.context.init_context(level)
         self.context.config_context(config_dict, level)