Fix ValueError when crating a copy of a report

This fixes #1
Merge pull request #47 from smeinel/master

When copying a report in Python 2.6.8, a ValueError gets thrown
Adds "Load url from future" in order to not crash on Django 1.4.2
Merge pull request #50 from pedrospdc/hotfix/django-1.4-compatibility-template

Adds "Load url from future" in order to not crash on Django 1.4.2
Update README.md

Trying to be more clear about why django-sis is referenced.