Move the Place comparator to an init file to have .comparing and not .comparing.comparing

doc/build/html/example/database/load_image_posorient.png

doc/build/html/example/database/load_image_posorient.py

doc/build/html/example/database/load_image_rowid.hires.png

doc/build/html/example/database/load_image_rowid.pdf

doc/build/html/example/database/load_image_rowid.png

doc/build/html/example/database/load_image_rowid.py

doc/build/html/example/processing/apcv.hires.png

doc/build/html/example/processing/apcv.pdf

doc/build/html/example/processing/apcv.png

doc/build/html/example/processing/apcv.py

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...ld/html/example/processing/contrast_weighted_nearness.pdf

...ld/html/example/processing/contrast_weighted_nearness.png

...ild/html/example/processing/contrast_weighted_nearness.py

...uild/html/example/processing/michelson_contrast.hires.png

doc/build/html/example/processing/michelson_contrast.pdf

doc/build/html/example/processing/michelson_contrast.png

doc/build/html/example/processing/michelson_contrast.py

doc/build/html/example/processing/pcv.py

doc/build/html/example/processing/scene.hires.png