copy context owner when user copied a config/metaconfig

Context owner is now in values (no more in settings).
The context owner is set in storage.
So when copy/deepcopy a config, owner is copied to.
For user, when export values, context owner is not returned by default.

tiramisu/setting.py

@@ -325,7 +325,9 @@ undefined = Undefined()
 #____________________________________________________________
 class Settings(object):
     "``config.Config()``'s configuration options settings"
-    __slots__ = ('_owner', '_p_', '_pp_', '__weakref__')
+    __slots__ = ('_p_',
+                 '_pp_',
+                 '__weakref__')
 
     def __init__(self,
                  properties,
@@ -340,7 +342,6 @@ class Settings(object):
                         - sqlite3 -> persistent
         """
         # generic owner
-        self._owner = owners.user
         self._p_ = properties
         self._pp_ = permissives
 
@@ -779,17 +780,3 @@ class Settings(object):
         self._read(rw_remove,
                    rw_append,
                    context)
-
-    #____________________________________________________________
-    # default owner methods
-
-    def setowner(self,
-                 owner):
-        ":param owner: sets the default value for owner at the Config level"
-        if owner in forbidden_owners:
-            raise ValueError(_('set owner "{0}" is forbidden').format(str(owner)))
-
-        self._owner = owner
-
-    def getowner(self):
-        return self._owner