Add support for Tuya MCU 0x1C (obtain local time) (#1344)

* Fix some Tuya devices not handling commands sent without delay

* Also do not report WiFi status if MCU does not support it

* Support Tuya MCU 0x1c command (obtain local time)

* Use #ifdef USE_TIME to handle optional dependency on RTC

* Rename Tuya clock config variable to time to be consistent with the codebase

* Add tuya time configuration to test4

esphome/components/tuya/__init__.py

@@ -1,7 +1,8 @@
+from esphome.components import time
 import esphome.codegen as cg
 import esphome.config_validation as cv
 from esphome.components import uart
-from esphome.const import CONF_ID
+from esphome.const import CONF_ID, CONF_TIME_ID
 
 DEPENDENCIES = ['uart']
 
@@ -11,6 +12,7 @@ Tuya = tuya_ns.class_('Tuya', cg.Component, uart.UARTDevice)
 CONF_TUYA_ID = 'tuya_id'
 CONFIG_SCHEMA = cv.Schema({
     cv.GenerateID(): cv.declare_id(Tuya),
+    cv.Optional(CONF_TIME_ID): cv.use_id(time.RealTimeClock),
 }).extend(cv.COMPONENT_SCHEMA).extend(uart.UART_DEVICE_SCHEMA)
 
 
@@ -18,3 +20,6 @@ def to_code(config):
     var = cg.new_Pvariable(config[CONF_ID])
     yield cg.register_component(var, config)
     yield uart.register_uart_device(var, config)
+    if CONF_TIME_ID in config:
+        time_ = yield cg.get_variable(config[CONF_TIME_ID])
+        cg.add(var.set_time_id(time_))