reworked theme for Asciidoctor 1.5.0

- switched to OSS web fonts in asciidoctor theme
- use custom print styles
- simplify table styles
- remove some unused built-in styles from Foundation
- use https scheme for fonts
Match conventions of DocBook PDF output for books

For asciidoctor/asciidoctor#952.
Add missing border styles in default stylesheet
Merge pull request #12 from leif81/table-border-styles

Add missing border styles in default stylesheet
style audioblock title; fix title styles; set padding-top on toc; increase print margin
change mathblock to stemblock
Merge PR #13 from @leif81
define text-rendering for subheadings
remove clearing above #content container
update themes
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
added aim42 sass file
font import for aim42 and initial innoq template (don't use, yet)