Improve relationship between module and bundle

Logic now:
 - module only: stand-along item going to CTAN on its own
 - bundle only: bundle of modules to got to CTAN together
 - bundle and module: module which is only sent to CTAN as part of a bundle
   but can e.g. installed or have tests run on its own


git-svn-id: http://www.latex-project.org/svnroot/experimental/trunk@5032 de43f980-851b-0410-b2f7-c40aca1f87e0