Make views.helpers.html_menu MenuItem classes and logic.menu MenuItem classes
more closely related. This is part of some refactoring in my working copy
to keep soc/logic/site/sidebar.py from having to deal with html_menu classes
(which is like having view code in the controller, which is bad).
Change indentation level to 2 (from 4) and rename MCE_DEF_SETTINGS to
DEF_MCE_SETTINGS to match the "default constant" naming convention elsewhere
in the code.