Add support for Tuya Sensors (#1088)

* Add Tuya sensor

* Add tuya sensor to test4

* Forgot id

esphome/components/tuya/sensor/__init__.py

@@ -0,0 +1,28 @@
+from esphome.components import sensor
+import esphome.config_validation as cv
+import esphome.codegen as cg
+from esphome.const import CONF_ID
+from .. import tuya_ns, CONF_TUYA_ID, Tuya
+
+DEPENDENCIES = ['tuya']
+
+CONF_SENSOR_DATAPOINT = "sensor_datapoint"
+
+TuyaSensor = tuya_ns.class_('TuyaSensor', sensor.Sensor, cg.Component)
+
+CONFIG_SCHEMA = sensor.SENSOR_SCHEMA.extend({
+    cv.GenerateID(): cv.declare_id(TuyaSensor),
+    cv.GenerateID(CONF_TUYA_ID): cv.use_id(Tuya),
+    cv.Required(CONF_SENSOR_DATAPOINT): cv.uint8_t,
+}).extend(cv.COMPONENT_SCHEMA)
+
+
+def to_code(config):
+    var = cg.new_Pvariable(config[CONF_ID])
+    yield cg.register_component(var, config)
+    yield sensor.register_sensor(var, config)
+
+    paren = yield cg.get_variable(config[CONF_TUYA_ID])
+    cg.add(var.set_tuya_parent(paren))
+
+    cg.add(var.set_sensor_id(config[CONF_SENSOR_DATAPOINT]))