Bienenwaage 5.0 backlog

• Improve configuration section within README.rst.

• Pull all configuration variables like “Taragewicht_A” to the top of the sketch, always use uppercase letters.

• Improve configuration for weather underground.

• Extend DS18B20 subsystem to use an arbitrary number of sensors.

• Check if we can make this sketch compatible with ESP8266 again.

• Make ADC pin A0 configurable.