Update README.md

Author: pbiecek

README.md

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 [![CRAN_Status_Badge](http://www.r-pkg.org/badges/version/randomForestExplainer)](https://cran.r-project.org/package=factorMerger)
 [![Pending Pull-Requests](http://githubbadges.herokuapp.com/MI2DataLab/randomForestExplainer/pulls.svg)](https://github.com/MI2DataLab/randomForestExplainer/pulls)
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 A set of tools to understand what is happening inside a Random Forest. A detailed discussion of the package and importance measures it implements can be found here: [Master thesis on randomForestExplainer](https://rawgit.com/geneticsMiNIng/BlackBoxOpener/master/randomForestExplainer_Master_thesis.pdf).