Move document sidebar entries extraction to document.View
This way other modules can benefit from the same logic. Also make use
of the sidebar.getSidebarMenu method so that getMenusForScope is no
longer specific to full menu's.
Patch by: Sverre Rabbelier
"""Multi-consumer multi-producer dispatching mechanism
Originally based on pydispatch (BSD) http://pypi.python.org/pypi/PyDispatcher/2.0.1
See license.txt for original license.
Heavily modified for Django's purposes.
"""
from django.dispatch.dispatcher import Signal