Seeed Sunlight sensor

[pkrahmer]

Adding this as a custom input, as this is using the groove i2c library. In my tests this does not affect operation of the other i2c inputs, but I guessed you might prefer it outside of the mycodo main code.

[kizniche]

I'm fine with this being included in the built-in set. I'd include the sensor name, though, so perhaps:

'input_name': 'SI114x Sunlight Sensor',