anchor.diff:     whisker_0.3-2.tar.gz \
      bitops_1.0-6.tar.gz \
      RCurl_1.95-4.8.tar.gz \
  -   Rcpp_0.12.13.tar.gz \
  +   Rcpp_0.12.14.tar.gz \
      plyr_1.8.4.tar.gz \
      R6_2.2.2.tar.gz \
      mime_0.5.tar.gz \
  
positive.code: # update the R packages we will need for knitr
  RUN DEBIAN_FRONTEND=noninteractive wget \
     https://mirrors.nics.utk.edu/cran/src/contrib/knitr_1.17.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/yaml_2.1.14.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/Rcpp_0.12.13.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/htmltools_0.3.6.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/caTools_1.17.1.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/bitops_1.0-6.tar.gz \
  
negative.code:    https://mirrors.nics.utk.edu/cran/src/contrib/openssl_0.9.9.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/withr_2.1.0.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/brew_1.0-6.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/stringi_1.1.6.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/magrittr_1.5.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/stringr_1.2.0.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/Archive/roxygen2/roxygen2_5.0.1.tar.gz \
  