Changes to Resampling-Based Mean-Variance Efficient Portfolio

added the new required request property assetsMeanReturns

removed the request property assetsReturns

removed the request property assetsReturnsUncertaintyIntervals

removed the request property constraints/portfolioReturn

added the new optional request property assetsMeanReturnsUncertaintyIntervals

added the new optional request property constraints/portfolioMeanReturn