Allow initial weight vectors in LogisticRegression.
Also move LogisticGradient to the LogisticRegression file and fix the
unit tests log path.
Rename loss -> stochasticLoss and add a note to explain why we have
multiple train methods.
Change weights to be Array[Double] in LR model.
Also ensure weights are initialized to a column vector.
Return Array[Double] from SGD instead of DoubleMatrix
Merge pull request #710 from shivaram/ml-updates

Updates to LogisticRegression