major rework of AsciiDoc component

- rework styles
- update color palette in asciidoctor theme
- drop unused variables
- use Foundation radius function by default
- use csshrink to further minimize stylesheet size
update styles for print; adjust spacing around header

- update and consolidate print styles
- only repeat URL for links not marked as "bare"
- make spacing above header consistent
- don't style the first part like a doctitle
- center sidebar title
- show language hover text in print styles
- use 0 to clear border instead of none
remove line-height override in sidebar; tweak language text hover position
Merge https://github.com/asciidoctor/asciidoctor-stylesheet-factory
integrated changes from upstream