support for xiaomi aqara thermometer and few other fixes (#18)

* import pip._internal.main to work with pip version > 10

* make auth optional and add support for an optional port

* add worker for xiaomi aqara thermometer

* add support for optional global publishing topic_prefix

* Update config.yaml.example

workers/mithermometer.py

@@ -0,0 +1,37 @@
+from interruptingcow import timeout
+from mqtt import MqttMessage
+from workers.base import BaseWorker
+
+REQUIREMENTS = ['mithermometer']
+
+monitoredAttrs = ["temperature", "humidity", "battery"]
+
+class MithermometerWorker(BaseWorker):
+  def _setup(self):
+    from mithermometer.mithermometer_poller import MiThermometerPoller
+    from btlewrap.bluepy import BluepyBackend
+
+
+    for name, mac in self.devices.items():
+      self.devices[name] = MiThermometerPoller(mac, BluepyBackend)
+
+  def status_update(self):
+    ret = []
+    for name, poller in self.devices.items():
+      try:
+        ret += self.update_device_state(name, poller)
+      except RuntimeError:
+        pass
+
+    return ret
+
+  @timeout(8.0)
+
+  def update_device_state(self, name, poller):
+
+    ret = []
+    for attr in monitoredAttrs:
+
+      ret.append(MqttMessage(topic=self.format_topic(name, attr), payload=poller.parameter_value(attr)))
+
+    return ret