move examples from the help page ?knitr::spin since CRAN sent me a note, which said it wouldn't be possible to write to the current dir during R CMD check
move examples from the help page ?knitr::spin since CRAN sent me a note, which said it wouldn't be possible to write to the current dir during R CMD check

yihui/yihui.name,yihui/yihui.name,yihui/yihui.name