Merged from trunk 7269:7283

   Merged from trunk 7269:7283

   +------------------------------------------------------------------------+
   | 7270   | sync MAILSUBJECT in make.conf with make.globals               |
   | genone |                                                               |
   |--------+---------------------------------------------------------------|
   | 7271   | s/node/atom/ and other minor updates                          |
   | genone |                                                               |
   |--------+---------------------------------------------------------------|
   | 7272   | Make PackageSet to behave more like a real set, and change    |
   | genone | loading logic a bit to avoid unnecessary reloads for editable |
   |        | sets                                                          |
   |--------+---------------------------------------------------------------|
   | 7273   | use a more logical approach for editable sets                 |
   | genone |                                                               |
   |--------+---------------------------------------------------------------|
   | 7274   | fix load logic for editable sets once more                    |
   | genone |                                                               |
   |--------+---------------------------------------------------------------|
   | 7275   | ignore already applied glsas when loading the security set    |
   | genone |                                                               |
   |--------+---------------------------------------------------------------|
   | 7276   | add support for metadata                                      |
   | genone |                                                               |
   |--------+---------------------------------------------------------------|
   | 7277   | fix metadata parsing for file-based sets, add support for     |
   | genone | user-defined file sets in test code                           |
   |--------+---------------------------------------------------------------|
   | 7278   | disable FEATURES=gpg as it's unmaintained, useless and likely |
   | genone | broken for many people                                        |
   |--------+---------------------------------------------------------------|
   | 7279   | replace emerge.AtomSet with portage.sets.InternalPackageSet   |
   | genone |                                                               |
   |--------+---------------------------------------------------------------|
   | 7280   | break recursion cycle                                         |
   | genone |                                                               |
   |--------+---------------------------------------------------------------|
   | 7281   | Replace emerge.SystemSet with                                 |
   | genone | portage.sets.profiles.PackagesSystemSet                       |
   |--------+---------------------------------------------------------------|
   | 7282   | break another recursion cycle, add special subclass for       |
   | genone | "world" to handle locking                                     |
   |--------+---------------------------------------------------------------|
   | 7283   | Replace emerge.WorldSet with portage.sets.files.WorldSet      |
   | genone |                                                               |
   +------------------------------------------------------------------------+

svn path=/main/branches/prefix/; revision=7284