Merge branch 'content_header' of https://github.com/RomanZacharia/pye…

…thapp into RomanZacharia-content_header

pyethapp/rpc_client.py

@@ -121,7 +121,7 @@ def __init__(self, host='127.0.0.1', port=4000, print_communication=True,
         "specify privkey for local signing"
         if transport is None:
             self.transport = HttpPostClientTransport('{}://{}:{}'.format(
-                'https' if use_ssl else 'http', host, port))
+                'https' if use_ssl else 'http', host, port), headers={'content-type': 'application/json'})
         else:
             self.transport = transport
         self.print_communication = print_communication