Add support for sample with return
Implemented Donald Knuth's algorithm for Poisson random generation. Removed colt dependency.
hide the flowDef to improve encapsulation and facilitate creation of flows that do not have a flowDef such as riffle jobs
Merge pull request #497 from pcting/develop

FlowSkipStrategy and FlowStepStrategy
merge by hand
rename sampleWithReturn to sampleWithReplacement
Merge pull request #495 from itaibenari/develop

Add support for sample with return
Merge pull request #499 from tresata/feat-hide-flowdef

hide the flowDef to improve encapsulation and facilitate creation of flo...