Spot when pressure sensor has stalled and reset it.

[amcewen]

What does this implement/fix? Explain your changes.

This fixes the problem with the MPL3115A2 on the pysense board occasionally hanging. The code gets into an infinite loop if the sensor fails to respond over I2C.

The code now spots if there hasn't been a response, and resets the MPL3115A2 sensor. The failure is communicated to the main code as an exception, and no result is returned, but the next time the call is made the sensor will be reset and will return values again.

Does this close any currently open issues?

This will close issue #46.

Where has this been tested?

• Tested on a pysense board with a LoPy4
• (sysname='LoPy4', nodename='LoPy4', release='1.18.1.r1', version='v1.8.6-849-b0520f1 on 2018-08-29', machine='LoPy4 with ESP32', lorawan='1.0.2', sigfox='1.0.1')

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[gijsio]

Hi,
Sorry for the extremely long delay.
Thanks a lot for the contribution, in the meantime we moved some files around and, instead, merged your solution in #146.

Best,
Gijs