Can we use bwpropfilt to more cleverly filter the BW image?

[raacampbell]

See here: ea6042e1cd981be6b63aac6103943c5207a000ff
We are using a dumb size filter. Maybe bwpropfilt would be better? Could we even remove boxes of weird size as boundingBoxesFromLastSection.binarizeImage does?

In theory that stuff should not be there, since it's been filtered already. But you never know... Check.