Intro measurements

The Cumulocity Python SDK's measurements API (see also classes Measurements and Measurement) includes the following additions to allow easy creation of standard measurement values including units.

Effectively, each of the value classes represent a value fragment, e.g. Celsius:

{"unit": "°C", "value": 22.8}

These values can easily be combined, e.g. when constructing a measurement:

m = Measurement(
    type='cx_LevelMeasurement', source=device_id, time='now',
    cx_Levels={
        'oil': Liters(8.4),
        'gas': Liters(223.18),
        'h2o': Liters(1.2),
        'bat': Percentage(85)
    })