added scikit-learn example
added scikit-learn example

chrinide/optunity,chrinide/optunity,claesenm/optunity,claesenm/optunity,claesenm/optunity,chrinide/optunity,MarkAWard/optunity,MarkAWard/optunity,MarkAWard/optunity,MarkAWard/optunity,claesenm/optunity,chrinide/optunity