prefs: split .parent into .base/.container to hopefully make things clearer
http://bugs.activestate.com/show_bug.cgi?id=101666

Note that this, for now, intentionally breaks looking at language prefs for
useTabs, indentWidth, and tabWith from documents.  That will be fixed in a
follow-up patch.

(integrated from komodo (trunk) change 85336 by marky)

git-svn-id: http://svn.openkomodo.com/repos/openkomodo/trunk@14373 b87d16e7-d29f-4ee1-b5ec-817d645d335f