Draft: Sensing Measurement Processing

Added the following classes: sensing.py: SensingMeasurement sensing.py: ProcessSensingMeasurement

Added the following methods: sensing.py/SensingModel: pcal_analog_aa_filter_response sensing.py/SensingModel: dcpd_analog_aa_filter_response

(The methods added above will likely need to be modified as they are misplaced or can be merged into one with the appropriate addition of a model_file option)

Added data_files folder to be used for the examples and the unit tests.

Added example file to show how to use the classes.

Added a model in model_files to be used with examples and unit test.

Missing unit tests for the measurement and process methods.

Issues #22 (closed) #11 (closed) #23 (closed)