Removed {::nomarkdown}{:/} wrapping picturefill
Removed {::nomarkdown}{:/} wrapping picturefill

- only tested on redcarpet markdown library
Faiz7412/jekyll-picture-tag,kremalicious/jekyll-picture-tag,Faiz7412/jekyll-picture-tag,robwierzbowski/jekyll-picture-tag,Faiz7412/jekyll-picture-tag,kremalicious/jekyll-picture-tag,intrinseca/jekyll-picture-tag,intrinseca/jekyll-picture-tag