use django.conf.urls (django 1.5)

django.conf.urls.defaults is deprecated; use django.conf.urls instead
Load url tag from future

Provides necessary Django 1.5 compatabilty for default template use.
Fix Django DateTimeField warning on migrations

When running unit tests against my django apps, I am tired of seeing the warning from actstream's internal migrations that say: `DateTimeField received a naive datetime (2013-05-06 18:08:44.244158) while time zone support is active.`. This change removes the warning by using a workaround needed for South v0.7.6.
Added try/ catch to avoid stream dying on one invalid item
Merge branch 'master' of https://github.com/tclancy/django-activity-stream
Merge branch 'url-tag-update' of https://github.com/bennylope/django-activity-stream
Merge branch 'master' of https://github.com/laginha/django-activity-stream