* Add test for svm model with probability estimation
* Extract buildPredictCommand method
* Fix test to use PHP_EOL
* Add predictProbability method (not completed)
* Add test for DataTransformer::predictions
* Fix SVM to use PHP_EOL
* Support probability estimation in SVM
* Add documentation
* Add InvalidOperationException class
* Throw InvalidOperationException before executing libsvm if probability estimation is not supported
* Multiple training data sets allowed
* Tests with multiple training data sets
* Updating docs according to #38
Documenting all models which predictions will be based on all
training data provided.
Some models already supported multiple training data sets.
