add tests for inline GIF
add tests for inline GIF

dsisnero/asciidoctor-pdf,asciidoctor/asciidoctor-pdf,mojavelinux/asciidoctor-pdf,Hextremist/asciidoctor-pdf,Hextremist/asciidoctor-pdf,dsisnero/asciidoctor-pdf,asciidoctor/asciidoctor-pdf,mojavelinux/asciidoctor-pdf