Ensure that the icon PDFs actually get installed.

Author: mdehoon

setupext.py

@@ -601,6 +601,7 @@ def get_package_data(self):
                 'mpl-data/images/*.xpm',
                 'mpl-data/images/*.svg',
                 'mpl-data/images/*.gif',
+                'mpl-data/images/*.pdf',
                 'mpl-data/images/*.png',
                 'mpl-data/images/*.ppm',
                 'mpl-data/example/*.npy',