BME680 Refactor

Add a sensor-class interface for the BME680 which is more pythonic than access through raw functions. This class also functions as a context-manager to automatically turn off the sensor once it is no longer needed.

The new interface allows a number of different ways to access the sensor:

import bme680

with bme680.Bme680() as environment:
    # Do a measurement, just for temperature
    t = environment.temperature

    # Do a measurement, just for humidity
    h = environment.humidity

    # Get all measurements in a single call; this is faster
    d = environment.get_data()
    t = d.temperature
    h = d.humidity

# Without context-manager
env = bme680.Bme680()
t = env.temperature
# Turn off manually:
env.close()

Closes #107 (closed)

cc @chris007

Documentation/pycardium/bme680.rst

@@ -2,6 +2,7 @@
 
 ``bme680`` - Environmental Sensor
 =================================
+Allows access to environmental data of card10's surroundings.
 
 **Example**:
 
@@ -9,17 +10,28 @@
 
    import bme680, utime
 
-   bme680.init()
+   with bme680.Bme680() as environment:
+       while True:
+           d = environment.get_data()
 
-   while True:
-       temperature, humidity, pressure, resistance = bme680.get_data()
+           print("Temperature:    {:10.2f} °C".format(d.temperature))
+           print("Humidity:       {:10.2f} % r.h.".format(d.humidity))
+           print("Pressure:       {:10.2f} hPa".format(d.pressure))
+           print("Gas Resistance: {:10.2f} Ω".format(d.resistance))
 
-       print("Temperature:    {:10.2f} °C".format(temperature))
-       print("Humidity:       {:10.2f} % r.h.".format(humidity))
-       print("Pressure:       {:10.2f} hPa".format(pressure))
-       print("Gas Resistance: {:10.2f} Ω".format(resistance))
+           utime.sleep(1)
 
-       utime.sleep(1)
+Sensor Class
+------------
+
+.. autoclass:: bme680.Bme680
+   :members:
+
+Deprecated Interface
+--------------------
+The following functions should no longer be used directly.  The only exist for
+compatibility as they were the old BME680 interface in previous firmware
+versions.
 
 .. py:function:: init()
 
@@ -29,6 +41,8 @@
    :py:func:`bme680.init`.
 
    .. versionadded:: 1.4
+   .. deprecated:: 1.10
+      Use the :py:class:`bme680.Bme680` class instead.
 
 .. py:function:: get_data()
 
@@ -38,9 +52,13 @@
       ``pressure`` (hPa) and ``gas resistance`` (Ohm).
 
    .. versionadded:: 1.4
+   .. deprecated:: 1.10
+      Use the :py:class:`bme680.Bme680` class instead.
 
 .. py:function:: deinit()
 
    Deinitialize the sensor.
 
    .. versionadded:: 1.4
+   .. deprecated:: 1.10
+      Use the :py:class:`bme680.Bme680` class instead.

[xiretza]

Documentation still needs adjusting:

-           print("Temperature:    {:10.2f} °C".format(d.temperature))
-           print("Humidity:       {:10.2f} % r.h.".format(d.humidity))
-           print("Pressure:       {:10.2f} hPa".format(d.pressure))
-           print("Gas Resistance: {:10.2f} Ω".format(d.resistance))
+           print("Temperature:    {:10.2f} °C".format(d.temperature()))
+           print("Humidity:       {:10.2f} % r.h.".format(d.humidity()))
+           print("Pressure:       {:10.2f} hPa".format(d.pressure()))
+           print("Gas Resistance: {:10.2f} Ω".format(d.gas_resistance()))

[rahix]

No, because this is the result of environment.get_data(), which is a namedtuple.

[xiretza]

Oh, right, sorry, didn't look far enough. d.resistance should still be d.gas_resistance though, right?