Instead of using a separate data structure to request that a PD remain powered during deep sleep,
we do the same within the main LPM data structure through an additional field.
This allows us to maintain only one linked list of LPM modules and overall improves code clarity
* Query the sensor about its state, rather than using variables in the driver
* Correctly put the sensor to deep sleep
* Fix doxygen comments
* Don't turn off the sensor in examples since it is no longer needed
