Merged from trunk 9335:9351

   Merged from trunk 9335:9351

   | 9336    | Fix package selection logic in order to prevent downgrade in |
   | zmedico | cases when selective is True and the currently installed     |
   |         | version does not have a matching ebuild in the tree. For     |
   |         | example, this type of situation is likely to occur if the    |
   |         | user somehow obtains a binary package that has a newer       |
   |         | version than any of the ebuilds in the portage tree. If      |
   |         | package maintainers want to encourage a downgrade in a case  |
   |         | like this then they should use package.mask so that the user |
   |         | receives a warning about the installed package being masked. |

   | 9337    | Fix --newuse reinstall logic broken by the previous commit.  |
   | zmedico |                                                              |

   | 9338    | Update the DepPriority documentation so that the table shows |
   | zmedico | all the currently supported priorities and categories.       |

   | 9339    | Bug #201045 - Use a topological sort to create an unmerge    |
   | zmedico | order such that each package is unmerged before it's         |
   |         | dependencies. This is necessary to avoid breaking things     |
   |         | that may need to run during pkg_prerm or pkg_postrm phases.  |

   | 9340    | Make depclean code filter out blocker atoms where            |
   | zmedico | appropriate.                                                 |

   | 9341    | Fix depclean breakage so that it doesn't clean some packages |
   | zmedico | that shouldn't be cleaned.                                   |

   | 9342    | Add missing % x (bug #208946, comment #2).                   |
   | zmedico |                                                              |

   | 9343    | Fix reversed order of parent/child parameders to             |
   | zmedico | digraph.add().                                               |

   | 9344    | Remove IUSE.invalid from qawarnings since there's no reason  |
   | zmedico | for it not to be fatal. Thanks to Betelgeuse.                |

   | 9345    | In the action_depclean() topological sort, only add packages |
   | zmedico | to the graph if they are being removed.                      |

   | 9346    | Bug #201045 - Make unmerge() preserve the unmerge order of   |
   | zmedico | packages given to it by the user or depclean.                |

   | 9347    | Make sure all packages to be pruned or depcleaned are added  |
   | zmedico | to the graph, even when they don't have any dependencies.    |

   | 9348    | Now that unmerge() preserves the order that it's given, if   |
   | zmedico | two different slots of the same package are being unmerged   |
   |         | then they are not necessarily unmerged consecutively. To     |
   |         | make the display less confusing, never display packages as   |
   |         | "protected" or "omitted" when they actually belong to the    |
   |         | overall set of "selected" packages to be unmerged.           |

   | 9349    | Fix unmerge() breakage from due to pkgmap being changed from |
   | zmedico | a dict to a list.                                            |

   | 9350    | Fix the --depclean/--prune code to use visible() for         |
   | zmedico | visibility checks instead of the old portdbapi hack.         |

   | 9351    | Make LibraryConsumerSet.mapPathsToAtoms() produce slot atoms |
   | zmedico | so that atoms aren't restricted to the currently installed   |
   |         | version, making upgrades possible.                           |

svn path=/main/branches/prefix/; revision=9374