* Simplifying margin plotting in SVM examples (#8501)
* updated to use contour levels on decision function
* separating unbalanced class now uses a red line to show the change in the decision boundary when the classes are weighted
* corrected the target variable from Y to y
* DOC Updates to SVM examples
* Fixing flake8 issues
* Altered make_blobs to move clusters to corners and be more compact
* Reverted changes converting Y to y
* Fixes for flake8 errors
* Modify plot_custom_kernel for matplotlib v2 comp
Add `edgecolors` attribute in scatter plot for better visualization
in matplotlib version 2
Issue: #8364
* Modify plot_oneclass.py for matplotlib v2 comp
Add `edgecolors` attribute to scatter plot for better
visualization in matplotlib version 2
Issue: #8364
* Modify plot_rbf_parameters for matplotlib v2
Add `edgecolors` attribute to scatter plot for
better visualization.
Issue: #8364
* Modify plot_separating_hyperplane_unbalanced for matplotlib v2
Add `edgecolors` attribute to scatter plot for better visualization.
Issue: #8364
* Modify plo_svm_kernels for matplotlib v2
Add `edgecolors` attribute to scatter plot for better
visualization.
Issue: #8364
* Modify plot_svm_margin for matplotlib v2 comp
Add `edgecolors` attribute to scatter plot for better
visualization.
Issue: #8364
* Modify plot_svm_nonlinear for matplotlib v2
Add `edgecolors` attribute to scatter plot for matplotlib
version 2 compatibility
Issue: #8364
* Modify file for remove flake8 error
Remove extra white space.
Issue: #8364