broken packaging of DISIS externals

I just noticed that there's something wrong with the packaging of the DISIS externals. Some end up in extra/disis/, some are still in extra/, and some of the shared objects are missing (most notably, disis_wiimote.pd_linux). Which is pretty bad considering that the wiimote support is one of pd-l2ork's distinguishing features. ;-)

Upstream is unaffected (pd-l2ork still has all of these directly under extra/), so this is only in purr-data. And it is not only in my own packages, but also in your latest deb package (just checked the 16.04 one), so I guess that something got messed up in tar_em_up.sh or in the corresponding Makefile. (I can look into this myself if you're busy with other things.)