updated drivers and added pi version of abbflow

flow-monitor/flow-monitor.py

@@ -660,9 +660,11 @@ class start(threading.Thread, deviceBase):
     def flowmonitor_setlowflow(self, name, value):
         """Set the low flow limit"""
         try:
-            self.lowflow = value
+            self.lowflow = float(value)
             self.sendtodb("setlowflow", self.lowflow,0)
-            return True
+            PERSIST["lowflow"] = self.lowflow
+            persistence.store(PERSIST)
         except Exception as e:
             logger.error("Error during flomonitor_setlowflow: {}".format(e))
             return False
+        return True