improvement of protocol
refactoring

send in field order

receiver unpacking

refactoring of packer code

fields send, pack replacement
diff --git a/wally/sensors/api.py b/wally/sensors/api.py
index 6eed90a..ea73789 100644
--- a/wally/sensors/api.py
+++ b/wally/sensors/api.py
@@ -20,7 +20,8 @@
 
 
 class SensorConfig(object):
-    def __init__(self, conn, url, sensors, source_id, monitor_url=None):
+    def __init__(self, conn, url, sensors, source_id,
+                 monitor_url=None):
         self.conn = conn
         self.url = url
         self.sensors = sensors