Add centre/right paragraph alignment.
Internally mark hard line breaks.
Internally allow splitting texts at endpoints.
This is required in order to preserve a hard line break at the end of
the input.
Internally support text breaks in ascending order.
Intended as a workaround to `breaksRight` not including the status of
the end-of-text break.
Separate split list functions into a module.
Fix terminology for box layout bounds.
Test handling of empty lines.
Make RTL text overflow the left paragraph edge.
This behaviour is consistent with CSS Text Module Level 3.
BREAKING: Previously, all text would overflow the right paragraph edge,
regardless of text direction.
Fix handling of mixed line height.
Displace lines by the height of the tallest fragment in the previous
line, not the shortest one.
Remove paragraphLineHeight from Rich interface.
Test ultra narrow Arabic text.
Test unions of lists of rectangles.
Expose rect unions in public interface.
Implement unions of lists of rectangles.
Parametrise rectangle union bias.
Remove TODO which would require an API break.
Test shaping across intra-word breaks.