markdown 1.7

• The file argument of mark() will be treated as a file path only if the file exists and the value is not wrapped in I(). Previously, it would be treated as a file path when it has a file extension, which could lead to confusing errors like #100 (thanks, @LukasWallrich).

• When there are emojis in the text, mark() may fail to identify and embed web resources (thanks, @tdhock, yihui/knitr#2254).