anchor.diff:  RUN DEBIAN_FRONTEND=noninteractive wget \
      http://archive.linux.duke.edu/cran/src/contrib/knitr_1.15.1.tar.gz \
      http://archive.linux.duke.edu/cran/src/contrib/yaml_2.1.14.tar.gz \
  -   http://archive.linux.duke.edu/cran/src/contrib/Rcpp_0.12.19.tar.gz \
  +   http://archive.linux.duke.edu/cran/src/contrib/Rcpp_0.12.10.tar.gz \
      http://archive.linux.duke.edu/cran/src/contrib/htmltools_0.3.5.tar.gz \
      http://archive.linux.duke.edu/cran/src/contrib/caTools_1.17.1.tar.gz \
      http://archive.linux.duke.edu/cran/src/contrib/bitops_1.0-6.tar.gz \
  
positive.code:    stringr_1.2.0.tar.gz \
     knitr_1.15.1.tar.gz \
     yaml_2.1.14.tar.gz \
     Rcpp_0.12.19.tar.gz \
     htmltools_0.3.5.tar.gz \
     caTools_1.17.1.tar.gz \
     bitops_1.0-6.tar.gz \
  
negative.code:    bitops_1.0-6.tar.gz \
     caTools_1.17.1.tar.gz \
     digest_0.6.12.tar.gz \
     Rcpp_0.12.10.tar.gz \
     htmltools_0.3.5.tar.gz \
     yaml_2.1.14.tar.gz \
     stringi_1.1.3.tar.gz \
  