"Object" level error should not fail without --raise-on-error on segmentation

[PonteIneptique]

My current understanding of --raise-on-error is that it should act as a method for deeply "debugging" a set of document or Kraken directly. Unfortunately, the blla.segment has some raising at the line level which prevent the full document to be processed:

kraken/kraken/lib/segmentation.py

Lines 729 to 732 in 89adb86

	except Exception as e:
	raise
	logger.warning(f'Polygonizer failed on line {idx}: {e}')
	polygons.append(None)

I proposed a first potential patch in #442 but if I were to propose a "better" patch, I would probably add a raise_on_error parameter to blla.segment and segmentation.calculate_polygonal_environment to decide between logging and raising at line 730.

I'll propose a second patch, so that you don't have to code it yourself, and choose the version you prefer.

[mittagessen]

Thanks, I merged them.