Merged from trunk 7951:7959

   Merged from trunk 7951:7959

   | 7952    | Add set configuration framework in preparation for emerge    |
   | genone  | integration                                                  |

   | 7956    | first version of set integration in emerge                   |
   | genone  |                                                              |

   | 7957    | only add short names for sets if they begin with 'sets/'     |
   | genone  |                                                              |

   | 7958    | Generalize the first paragraph of the MASKED PACKAGES        |
   | zmedico | section and document binary package CHOST masking.           |

   | 7959    | replace category sets in test configuration with user sets   |
   | genone  |                                                              |

svn path=/main/branches/prefix/; revision=7961