Merged from trunk -r15280:15285

   Merged from trunk -r15280:15285

   | 15281   | Deprecate the first parameter of the portdbapi constructor   |
   | zmedico | since it is always the same as mysettings['PORTDIR'].        |

   | 15282   | Use tuples instead of lists for immutability.                |
   | zmedico |                                                              |

   | 15283   | For immutable config attributes, use shallow copy for speed  |
   | zmedico | and memory conservation.                                     |

   | 15284   | For immutable config attributes, use shallow copy for speed  |
   | zmedico | and memory conservation.                                     |

   | 15285   | For immutable config attributes, use shallow copy for speed  |
   | zmedico | and memory conservation.                                     |

svn path=/main/branches/prefix/; revision=15300