0.8.4-beta binary_sensors, other minor changes

Changes in 0.8.4 beta

• [BREAKING CHANGE] now the component spawns binary_sensor entities, that is, the binary sensor classes now work. After the update, new entities in the binary_sensor domain will be created for all your binary sensors.
• experimental support for YM-K1501 (Xiaomi Mijia Smart Kettle)
• minor fixes and improvements