~jaro/balkon

ref: 0975c99f8e8fc2f33c968daa8968444bb0c026c5 balkon/src/Data/Text/ParagraphLayout/Internal/ParagraphExtents.hs -rw-r--r-- 925 bytes 
Allow paragraphRect without point 0,0.

Parametrise rectangle union bias.

Separate interface-independent constants.