~jaro/balkon

ref: 81d758baf4c7f7ab803edccb4dd1bb7e82a4753d balkon/test/Data/Text d---------
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.