add xiaomi BLE Thermometer lywsd02 model support (#664)

* add xiaomi BLE Thermometer lywsd02 model support

* remove battery level

* Update sensor.py

to pass the lint test
https://github.com/esphome/esphome/pull/664

* fix trailing space


Co-authored-by: Guoxue <gx@m15.cn>
Co-authored-by: mr G1K <mr@g1k.ru>

esphome/components/xiaomi_lywsd02/sensor.py

@@ -0,0 +1,34 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome.components import sensor, esp32_ble_tracker
+from esphome.const import CONF_HUMIDITY, CONF_MAC_ADDRESS, CONF_TEMPERATURE, \
+    UNIT_CELSIUS, ICON_THERMOMETER, UNIT_PERCENT, ICON_WATER_PERCENT, CONF_ID
+
+DEPENDENCIES = ['esp32_ble_tracker']
+AUTO_LOAD = ['xiaomi_ble']
+
+xiaomi_lywsd02_ns = cg.esphome_ns.namespace('xiaomi_lywsd02')
+XiaomiLYWSD02 = xiaomi_lywsd02_ns.class_('XiaomiLYWSD02', esp32_ble_tracker.ESPBTDeviceListener,
+                                         cg.Component)
+
+CONFIG_SCHEMA = cv.Schema({
+    cv.GenerateID(): cv.declare_id(XiaomiLYWSD02),
+    cv.Required(CONF_MAC_ADDRESS): cv.mac_address,
+    cv.Optional(CONF_TEMPERATURE): sensor.sensor_schema(UNIT_CELSIUS, ICON_THERMOMETER, 1),
+    cv.Optional(CONF_HUMIDITY): sensor.sensor_schema(UNIT_PERCENT, ICON_WATER_PERCENT, 1),
+}).extend(esp32_ble_tracker.ESP_BLE_DEVICE_SCHEMA).extend(cv.COMPONENT_SCHEMA)
+
+
+def to_code(config):
+    var = cg.new_Pvariable(config[CONF_ID])
+    yield cg.register_component(var, config)
+    yield esp32_ble_tracker.register_ble_device(var, config)
+
+    cg.add(var.set_address(config[CONF_MAC_ADDRESS].as_hex))
+
+    if CONF_TEMPERATURE in config:
+        sens = yield sensor.new_sensor(config[CONF_TEMPERATURE])
+        cg.add(var.set_temperature(sens))
+    if CONF_HUMIDITY in config:
+        sens = yield sensor.new_sensor(config[CONF_HUMIDITY])
+        cg.add(var.set_humidity(sens))