MAINT Don't use deprecated 1d X (or deprecated matplotlib stuff) in examples.

examples/applications/plot_prediction_latency.py

examples/applications/plot_stock_market.py

examples/classification/plot_lda_qda.py

...ter/plot_feature_agglomeration_vs_univariate_selection.py

examples/decomposition/plot_pca_iris.py

examples/decomposition/plot_sparse_coding.py

examples/ensemble/plot_gradient_boosting_regression.py

examples/linear_model/plot_sgd_separating_hyperplane.py

examples/manifold/plot_compare_methods.py

examples/manifold/plot_manifold_sphere.py

...ighbors/plot_approximate_nearest_neighbors_scalability.py

examples/semi_supervised/plot_label_propagation_structure.py