Merge pull request #70 from bensadeghi/master

DecisionTree bump: added pruning, modified API
Bump RDatasets SHA1
Bump ProjectTemplate SHA1
Bump Resampling SHA1
Bump Languages SHA1
Bump kNN SHA1
Bump Graphs SHA1
Bump Clustering SHA1
Bump Calculus SHA1
Bump Benchmark SHA1
Bump FileFind SHA1
Bump DataFrames SHA1
Bump TextAnalysis SHA1
Bump Optim SHA1
bump Iterators SHA1 to eeb7909832
DecisionTree bump: bug fixes