resolves #97 add support for inline icon macro
resolves #97 add support for inline icon macro

- add support for inline icon macro
- allow font set to be changed globally (icon-set=<icon-set> attribute)
- allow font set to be changed per icon (set=<icon-set> attribute or append @<icon-set> to target)

mojavelinux/asciidoctor-pdf,Hextremist/asciidoctor-pdf,abatalev/asciidoctor-pdf,DavidGamba/asciidoctor-pdf,asciidoctor/asciidoctor-pdf,dsisnero/asciidoctor-pdf,abatalev/asciidoctor-pdf,hmflash/asciidoctor-pdf,asciidoctor/asciidoctor-pdf,mojavelinux/asciidoctor-pdf,hmflash/asciidoctor-pdf,theimdal/asciidoctor-pdf,Hextremist/asciidoctor-pdf,DavidGamba/asciidoctor-pdf,dsisnero/asciidoctor-pdf,theimdal/asciidoctor-pdf