~jaro/balkon

ref: 8b8b095a2d7cc321b520b3d3dc707f3f0501d2e3 balkon/test/Data/Text/ParagraphLayout d---------
Store span index in ResolvedSpan.
Link to Span using a generic wrapper.
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.