Update install_nbextension.sh
Update install_nbextension.sh

clean-up and, install debs from main PPA instead of "wget+dpkg"
OSGeo/OSGeoLive,guygriffiths/OSGeoLive,astroidex/OSGeoLive,PascalLike/OSGeoLive,kalxas/OSGeoLive,kalxas/OSGeoLive,kalxas/OSGeoLive,guygriffiths/OSGeoLive,PascalLike/OSGeoLive,astroidex/OSGeoLive,PascalLike/OSGeoLive,OSGeo/OSGeoLive,astroidex/OSGeoLive,OSGeo/OSGeoLive,PascalLike/OSGeoLive,astroidex/OSGeoLive,PascalLike/OSGeoLive,kalxas/OSGeoLive,OSGeo/OSGeoLive,guygriffiths/OSGeoLive,PascalLike/OSGeoLive,kalxas/OSGeoLive,kalxas/OSGeoLive,PascalLike/OSGeoLive,guygriffiths/OSGeoLive,guygriffiths/OSGeoLive,OSGeo/OSGeoLive,guygriffiths/OSGeoLive,guygriffiths/OSGeoLive,astroidex/OSGeoLive,OSGeo/OSGeoLive,astroidex/OSGeoLive,OSGeo/OSGeoLive,kalxas/OSGeoLive