[scribus] Scribus AppImage

[probono]

Hi a.l.e.,

the "Nightly" Scribus AppImages on http://impagina.org/download/ do
not run because the Python modules are not bundled (but should be):
me at host:~$ /home/me/Downloads/Scribus-git44e637c-glibc2.14.glibc2.14-x86_64.AppImage
ImportError: No module named site

This can be fixed by running, in the AppDir:
( cd usr/lib ; cp -r /usr/lib/python2.7 . )

Now it launches for me, without the error:
./AppRun

While we are at it, we could update to making a type 2 (squashfs
based) AppImage using appimagetool.

Regards,
probono