MMSCORE: same method for multiplying two predictors as introduced in r1636 for 1 predictor. The methods for 1 predictor is more than 2 to 2.5 faster than method used before. This method is faster because the line 
tXW= X.transpose()*W caused X to have not enough rows to let vectorizing work efficient. When using W*X the left-hand side has enough rows for vectorization. 

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/genabel@1638 edb9625f-4e0d-4859-8d74-9fd3b1da38cb