Introduce analysis.py for signal processing
Introduce audio class for DSP
Add variable decoding_format for analysis.py __decode_data()
Add privatized helper function __decode_data()
Add configurable windowing policy for audio data
Fix naming convention of window function

All adjusted to lower case
Add privatized function to window decoded data

Available window function:

- hann

- hamming

- blackman

- bartlett

- barthann
Add wrapper function for decode & window
Add privatized rfft function
Add function to compute magnitude from rfft coeff
Add function to convert from mangitude to dB
Outline standard dsp routine in wrapper function
Modularize config parameters into related class
Add mapping variables from freqs <-> bin indexes
Add function to populate freq <-> index mapping
Include mapping variables fill in analysis routine
Add clear mapping variables before (re)filling
Merge branch 'analysis'

Merge for development testing