Signal Processing 0.1.0

First release, for Ignition 8.1 (8.1.33 or newer) and 8.3 (8.3.3 or newer): 33 scipy.signal functions under
system.signal, with SciPy 1.18.1's names, parameters, defaults and results, in every scope.

Added

• Detrending and windows: detrend, get_window (every window except dpss, with the _symmetric and
  _periodic suffixes).
• Filter design: butter, cheby1, cheby2, ellip, bessel (every band type, 'ba', 'zpk' and 'sos'
  output, analog designs, fs); order selection buttord, cheb1ord, cheb2ord, ellipord; responses
  freqz, freqz_sos and its older name sosfreqz. Zeros, poles and responses are Python complex numbers.
• Filtering: lfilter, lfilter_zi, sosfilt, sosfilt_zi, filtfilt, sosfiltfilt.
• Smoothing: savgol_coeffs, savgol_filter (all five edge modes, derivatives), medfilt.
• Peaks: find_peaks (height, threshold, distance, prominence, width, plateau size), peak_prominences,
  peak_widths.
• Spectra: welch, periodogram, spectrogram (modes psd, complex, magnitude, angle, phase), hilbert.
• Resampling: resample, resample_poly (every padtype), decimate.
• Tests: random comparison with SciPy, property checks, invalid-call checks, an accuracy test run inside
  Ignition and a gateway-scope spot check.

Differences from SciPy

• Lists and tuples are interchangeable; signals are 1-D; None, NaN and infinity in the data raise ValueError.
• Where SciPy needs a numpy array, lists work: windows given as values, prominence_data, and welch and
  spectrogram input (SciPy 1.18.1 fails on plain lists there).
• Savitzky-Golay least squares are solved exactly, so coefficients stay correct at high orders where SciPy's lose
  accuracy.
• Equal-height peaks competing under distance are ranked by position, the later first (SciPy's choice depends
  on the CPU).
• resample_poly with padtype 'reflect' or 'antireflect' on one sample raises ValueError (SciPy crashes the
  Python process).
• Not supported: dpss windows, freqz's plot, filtfilt's method='gust', detrend functions passed as
  callables, dlti systems in decimate. Integer arguments (orders, lengths, factors) must be integers.