~jaro/balkon

ref: 2d69d190193e4edf1a137fc615b8eb0c895f1824 balkon/test/Data/Text/ParagraphLayout d---------
Implement absolute line heights with half-leadings.
Use CSS-compatible line height settings.
Fix pretty printing for fragmented spans.
Upgrade Fragment to contain pen position.
Clean up ParagraphConstruction.
Use infix operators for constructing test data.
Implement "plain" interface.
Create "plain" interface.
Add module for working with rectangle coordinates.
Add explicit scale to test font.
Separate tests by module.