Restructure functions for usability

[soumyaray]

• PLSmodel(mmMatrix, smMatrix, ...) : generates plsModel list
• SimplePLS(plsModel, data) : generates PLSEstimated
• PLSpredict(plsModel, trainData, testData, ...) : generates plsPredicted
• LMpredict(plsModel, trainData, testData, ...) : generates lmPredicted
• VisualizePredict(plsPredicted, ...)