~jaro/balkon

ref: 03d36342529a318aa40fa9da94e8555e2f2017d5 balkon/src/Data/Text/ParagraphLayout d---------
Calculate "normal" line height and pen position.
Use CSS-compatible line height settings.
Upgrade Fragment to contain pen position.
Use CSS3 terminology for fragments and containing block.
Avoid reimplementing Data.Text.Lazy.fromStrict.
Implement "plain" interface.
Use Rect in "plain" interface.
Create "plain" interface.
Add module for working with rectangle coordinates.
Separate modules.