Merged from trunk 9774:9799

   Merged from trunk 9774:9799

   | 9775    | Fix minor issues in the calculation of the number of parents |
   | zmedico | omitted from the slot collision display.                     |

   | 9777    | Fix the docstring for depgraph._dep_expand().                |
   | zmedico |                                                              |

   | 9779    | When checking atoms without categories against the installed |
   | zmedico | packages, just check for existence of the cat/pn rather that |
   |         | a full match.                                                |

   | 9785    | Add some docs for the DepcheckCompositeDB class.             |
   | zmedico |                                                              |

   | 9786    | Replace the fakdbapi class that is used to track depgraph    |
   | zmedico | state with a similar PackageVirtualDbapi class that uses     |
   |         | Package instances internally. This eliminates some           |
   |         | redundancy since the Package instances can be reused         |
   |         | elsewhere, unlike the internal data structures used by       |
   |         | fakedbapi.                                                   |

   | 9787    | Improve used of cached Package instances in                  |
   | zmedico | depgraph._select_pkg_from_graph().                           |

   | 9788    | Make FakeVartree use PackageVirtualDbapi instead of          |
   | zmedico | fakedbapi so that it can populate and utilize a cache of     |
   |         | Package instances.                                           |

   | 9789    | * Make depclean/prune use cached Package instances for       |
   | zmedico | visibility checks. * Make FakeVartree wrap dbapi.match() to  |
   |         | make sure the metadata in Package instances gets updated for |
   |         | any cpv that is returned from a match() call, since the      |
   |         | metadata can be accessed directly from the Package instance  |
   |         | instead of via aux_get().                                    |

   | 9794    | Use cached Package instances in depgraph.display().          |
   | zmedico |                                                              |

   | 9797    | Make sure that everything except Package nodes is ignored    |
   | zmedico | when doing the --buildpkgonly digraph.hasallzeros() check.   |

   | 9799    | Iterate over a copy of the digraph nodes so that removal     |
   | zmedico | can't break the iterator.                                    |

svn path=/main/branches/prefix/; revision=9807