jimhester/knitrBootstrap — pull request #4 by yihui (2013-06-11 21:37:53+00:00)
Title: the new version of markdown (0.5.5) is on CRAN now

so you do not need to install it from Github; in the next version of `knitr`, I will depend on `markdown >= 0.5.5`, so `install.packages('knitr')` will solve the problem of dependencies