Merged from trunk -r12619:12633

   Merged from trunk -r12619:12633

   | 12620    | unify code for unpacking of tar files                       |
   | SpankMan |                                                             |

   | 12621    | Bug #259124 - Inside EbuildFetcher._start(), pass the       |
   | zmedico  | NOCOLOR variable into the fetch environment, so that        |
   |          | --color=n is respected.                                     |

   | 12622    | Fix grabfile_package() to preprocess atoms before passing   |
   | zmedico  | them to isvalidatom() because isvalidatom() has gotten more |
   |          | strict since r12614. Thanks to ABCD for reporting.          |

   | 12623    | Bug #253904 - Add a lookahead mechanism inside              |
   | zmedico  | depgraph._dep_check_composite_db._visible() which masks     |
   |          | package choices that are likely to trigger slot conflicts.  |
   |          | Thanks to Vlastimil Babka <caster@g.o> for the suggestion.  |

   | 12624    | Call depgraph._dep_check_composite_db._clear_cache() inside |
   | zmedico  | depgraph._add_pkg() since                                   |
   |          | _dep_check_composite_db._visible() is now affected by which |
   |          | packages are added to the graph.                            |

   | 12625    | Make save_ebuild_env() filter NOCOLOR, and remove related   |
   | zmedico  | code from ebuild.sh since that variable is not loaded from  |
   |          | $T/environment anymore.                                     |

   | 12626    | Set svn:keywords Id on all files.                           |
   | zmedico  |                                                             |

   | 12628    | In python-3.0, the UserDict.DictMixin class has been        |
   | zmedico  | replaced by Mapping and MutableMapping from the collections |
   |          | module, but 2to3 doesn't currently account for this change: |
   |          | http://bugs.python.org/issue2876 As a workaround for the    |
   |          | above issue, implement Mapping and MutableMapping classes   |
   |          | as substitutes for UserDict.DictMixin so that code          |
   |          | converted via 2to3 will run.                                |

   | 12629    | Implement a substitute for UserDict.UserDict so that code   |
   | zmedico  | converted via 2to3 will run:                                |
   |          | http://bugs.python.org/issue2876                            |

   | 12630    | Implement UserDict.__contains__() and __iter__().           |
   | zmedico  |                                                             |

   | 12631    | Remove redundant ConfigLoaderKlass.__iter__() method.       |
   | zmedico  |                                                             |

   | 12632    | Fix classes that implement __iter__() to copy it to their   |
   | zmedico  | keys() method when running under >=python-3.0.              |

   | 12633    | For compatibility with python-3.0, use isinstance() instead |
   | zmedico  | of type().                                                  |

svn path=/main/branches/prefix/; revision=12651