Replace truncate_html_words with Truncator

For Django 1.6+ compatibility
Updated release notes
Updated django.conf.urls import location
Preserve Django 1.3 compatibility
Update release notes
Merge branch 'master' into django-1.6

Conflicts:
	docs/releases.rst
Reflect Django 1.3+ support in the README
Merge pull request #51 from caktus/django-1.6

Django 1.6 compatibility