Added PCA widget.
Add Classification tree widget
Add icon and fix signal types and handlers for classification tree widget
Tree widgets constructs the learner/classifier and sends it
Weights are optional.
Move init and predict to SklFitter base class.
Merge pull request #135 from lanzagar/sklfitter

Move functionality to SklFitter base class.
Fixed incorrectly generated code by cython.
Merge pull request #129 from janezd/classification-tree

Add Classification tree widget
Fix bugs in DiscreteVariable.find_compatible
Merge pull request #136 from thocevar/cython

Fixed incorrectly generated code by cython (BasketReader).
Easier wrapping of scikit-learn methods.
Do not pass Y in one-class svm.
Fix DiscreteVariable.find_compatible not to fail when there are no existing variables with this name
Add tests for DiscreteVariable.make
Compute examples and class distributions in tree nodes.
Merge pull request #140 from thocevar/tree

Compute examples and class distributions in tree nodes.
Add sampling option to heatmap widget.
Merge pull request #142 from astaric/heatmap-on-sample

Add sampling option to heatmap widget.
Added color scale options.