add *.gif to recursive-include supervisor/ui. closes #463

MANIFEST.in

@@ -7,6 +7,6 @@ include tox.ini
 include supervisor/version.txt
 include supervisor/skel *.conf
 include supervisor/tests/fixtures *.conf
-recursive-include supervisor/ui *.html *.css *.png
+recursive-include supervisor/ui *.html *.css *.png *.gif
 recursive-include docs *.rst *.css *.gif *.png
 recursive-exclude docs/.build *