added gifs to the package_data in setup.py.

Author: Phil Elson

setup.py

@@ -98,6 +98,7 @@
                               'mpl-data/fonts/ttf/RELEASENOTES.TXT',
                               'mpl-data/images/*.xpm',
                               'mpl-data/images/*.svg',
+                              'mpl-data/images/*.gif',
                               'mpl-data/images/*.png',
                               'mpl-data/images/*.ppm',
                               'mpl-data/example/*.npy',