refactor and add Correlation.fs included Vector and sequence modules; refactored the correlation function as a vetor optimized implementation into the Vector module, added different definitions of the auto and cross correlation functions
refactor and add Correlation.fs included Vector and sequence modules; refactored the correlation function as a vetor optimized implementation into the Vector module, added different definitions of the auto and cross correlation functions

CSBiology/FSharp.Stats,CSBiology/FSharp.Stats