resolves #463 show URI for link (PR #489)
resolves #463 show URI for link (PR #489)

- show URI for link if show-link-uri or media=print is set
- surround URI with square brackets instead of round brackets
- don't italicize URI
asciidoctor/asciidoctor-pdf,dsisnero/asciidoctor-pdf,Hextremist/asciidoctor-pdf,mojavelinux/asciidoctor-pdf,asciidoctor/asciidoctor-pdf,mojavelinux/asciidoctor-pdf,dsisnero/asciidoctor-pdf,Hextremist/asciidoctor-pdf