~jaro/balkon

ref: cb8797a9b1f79382d55a6160d7440bda9e312803 balkon/test/Data/Text/ParagraphLayout/Internal d---------
Implement generic pagination internally.
Test removing spaces around lines.
Remove collapsible spaces at beginning of lines.
Allow empty lines when hard line breaking.
Reduce test dependencies on fonts.
Properly use ICU locale identifiers.
Refactor line breaking.
Allow breaking at character bounds.
Implement trimming spaces at end of lines.
Move non-public modules into Internal namespace.