Use system.getHostname() everywhere
Replace os.environ['HTTP_HOST'] with system.getHostname(), as a
result we do not crash when 'HTTP_HOST' is unset now.
"""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