edgeplus

• added new threshold: EdgePlus (ScanTailor-Advanced/scantailor-advanced#48)

threshold

• threshold method: DjVuL, BiMod, Sauvola, Blur

warning

• fix warning by @plzombie (see #4 (comment))

ground

• update DjVuL: fix DjVuL ground: define mean bg and fg.
• main DjVuL no changes

logarithmic

• fix #4: logarithmic quality scale

quality

• added BG/FG quality parameter

strip

• strip repo, use files in djvulibre.

mask

• optional mask file.

init

• Init version