Finish refactor debugging

[nfahlgren]

Describe your changes
Finish converting functions to using the _debug module.

Type of update
Is this a: Feature enhancement

Associated issues
Closes #713

[codecov]

Codecov Report

Merging #848 (aa7f6a2) into master (aec9924) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##            master      #848    +/-   ##
==========================================
  Coverage   100.00%   100.00%            
==========================================
  Files          142       142            
  Lines         6207      6055   -152     
==========================================
- Hits          6207      6055   -152     

Flag	Coverage Δ
unittests	100.00% <100.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
plantcv/plantcv/cluster_contour_mask.py	100.00% <ø> (ø)
plantcv/plantcv/spectral_index/spectral_index.py	100.00% <ø> (ø)
plantcv/plantcv/threshold/threshold_methods.py	100.00% <ø> (ø)
...lantcv/plantcv/hyperspectral/extract_wavelength.py	100.00% <100.00%> (ø)
plantcv/plantcv/morphology/analyze_stem.py	100.00% <100.00%> (ø)
plantcv/plantcv/morphology/check_cycles.py	100.00% <100.00%> (ø)
plantcv/plantcv/morphology/find_branch_pts.py	100.00% <100.00%> (ø)
plantcv/plantcv/morphology/find_tips.py	100.00% <100.00%> (ø)
plantcv/plantcv/morphology/prune.py	100.00% <100.00%> (ø)
plantcv/plantcv/morphology/segment_angle.py	100.00% <100.00%> (ø)
... and 18 more