Add a script for modifying ISO images

With this script it's possible to add additional files into an ISO file.
If the file happens to be ks.cfg, the boot configs are tweaked so that
the kickstart is actually used.

Resolves: #503
Signed-off-by: Lubomír Sedlář <lsedlar@redhat.com>

setup.py

@@ -41,6 +41,7 @@ setup(
         'bin/pungi-fedmsg-notification',
         'bin/pungi-koji',
         'bin/pungi-make-ostree',
+        'bin/pungi-patch-iso',
     ],
     data_files      = [
         ('/usr/share/pungi', glob.glob('share/*.xsl')),