~jaro/balkon

ref: ca37c6e309c0e50ea21dbc823c34b4f21c38c977 balkon/src/Data/Text/ParagraphLayout/Internal/ProtoLine.hs -rw-r--r-- 3.7 KiB 
Allow explicit control of box collapsing.

Add extensible filter for invisible lines.

Handle ancestor boxes in rich layout.