- in dopush (?), we need to sort out synthetic fast forard
    this should not depend entirely on quilt mode
    but will always be needed if quiltmode_splitbrain
     * On push, if ff fixup mode enabled, check debian/changelog,
       and maybe make fake merge, maybe in dgit view, maybe
       elsewhere ?


Want tests for

 - start repo with old tag, push with new tag, run
   "old" dgit to push again with new tag, push again with
   old tag

 - rejecting push of same version with one tag when then the other


Test that, where appropriate, maint view tags are pushed to dgit git repo


 * Provide --gpbpq[=:] options

 * Document --quilt=unapplied|gbp|dpm

 * Mention new tag format in debian/changelog

 * Mention new --quilt=* in debian/changelog

 * Test all three new --quilt=unapplied|gbp|dpm

 * Mention in-archive copy fix in debian/changelog

 * Mention in changelog that:
   Remove lrfetchrefs at end of fetch_from_archive, for tidyness