P3K: use print as a function in the examples

examples/applications/face_recognition.py

examples/applications/plot_outlier_detection_housing.py

examples/applications/plot_species_distribution_modeling.py

examples/applications/plot_stock_market.py

examples/applications/plot_tomography_l1_reconstruction.py

examples/applications/svm_gui.py

examples/applications/topics_extraction_with_nmf.py

examples/applications/wikipedia_principal_eigenvector.py

examples/cluster/plot_adjusted_for_chance_measures.py

examples/cluster/plot_affinity_propagation.py

examples/cluster/plot_cluster_comparison.py

examples/cluster/plot_cluster_iris.py

examples/cluster/plot_color_quantization.py

examples/cluster/plot_dbscan.py

examples/cluster/plot_dict_face_patches.py

examples/cluster/plot_digits_agglomeration.py

...ter/plot_feature_agglomeration_vs_univariate_selection.py

examples/cluster/plot_kmeans_digits.py

examples/cluster/plot_kmeans_stability_low_dim_dense.py

examples/cluster/plot_lena_compress.py