Improve docstrings to improve readability of the code

[oesteban]

The core functions should feature a much more detailed description of what they are doing:

diagnostics-NME/findoutlie/outfind.py

Line 36 in 6653c80

""" Detect outliers given image file path 'filename'

diagnostics-NME/findoutlie/outfind.py

Line 65 in 6653c80

""" Detect outliers given image file path 'filename'

diagnostics-NME/findoutlie/outfind.py

Line 91 in 6653c80

""" Detect outliers given image file path 'filename'

diagnostics-NME/findoutlie/outfind.py

Line 128 in 6653c80

""" Detect outliers given image file path `filename`