allow monitor to be skipped when not defined

closes issue #3

clacksme/clacksme.py

@@ -192,7 +192,14 @@ def main():
     db.init(args.store, pragmas={'journal_mode': 'wal'})
     create_tables()
 
-    monitor_url = System.get_or_none(System.key == "monitor_url")
+    monitor_url_check = System.get_or_none(System.key == "monitor_url")
+    if monitor_url_check is None:
+        monitor_url = None
+    else:
+        if len(monitor_url_check.value) < 8:
+            monitor_url = None
+        else:
+            monitor_url = monitor_url_check.value
 
     log_queue = Queue()
     event_queue = Queue()
@@ -209,7 +216,7 @@ def main():
     logging.basicConfig(level=logging.DEBUG)
     logging.debug("starting up main")
     log_thread = threading.Thread(target=logger_thread, 
-        args=(log_queue,monitor_url.value,))
+        args=(log_queue,monitor_url,))
     log_thread.start()
     e_thread = threading.Thread(target=event_thread, args=(event_queue,))
     e_thread.start()