Merge with mainline

Merge with mainline
Patches applied:

 * apt@packages.debian.org/apt--main--0--patch-93
   Merge with mvo

 * michael.vogt@ubuntu.com--2005/apt--mvo--0--patch-22
   * added myself to uploaders, changelog is signed with mvo@debian.org and in sync with the debian/experimental upload

 * michael.vogt@ubuntu.com--2005/apt--mvo--0--patch-23
   * apt-cache show <virtual-pkg> shows all virtual packages instead of nothing (thanks to otavio)

 * michael.vogt@ubuntu.com--2005/apt--mvo--0--patch-24
   * changelog updated

 * michael.vogt@ubuntu.com--2005/apt--mvo--0--patch-25
   * make pinning on component work again (we just use the section, as apt-0.6 don't use per-section Release files anymore)

 * michael.vogt@ubuntu.com--2005/apt--mvo--0--patch-27
   * updated the changelog

 * michael.vogt@ubuntu.com--2005/apt--mvo--0--patch-28
   * merged with my apt--fixes--0 branch

 * michael.vogt@ubuntu.com--2005/apt--mvo--0--patch-29
   * added a missing OpProgress::Done() in depCache::Init(), removed the show-virtual-packages patch in apt-cache because matt does not like him :/

 * michael.vogt@ubuntu.com--2005/apt--mvo--0--patch-30
   * fix a stupid bug in the depcache::Init() code

 * michael.vogt@ubuntu.com--2005/apt--mvo--0--patch-31
   * merged/removed conflicts with apt--main--0

 * michael.vogt@ubuntu.com--2005/apt--mvo--0--patch-32
   * merged apt--main and make sure that the po files come from apt--main (because they are more recent)