Update quickstart.txt

SlimIt main domain has expired
Update settings.txt
Merge pull request #555 from francescozaia/patch-1

Patch 1
Run automated tests on Django 1.7
Merge pull request #556 from frewsxcv/develop

Run automated tests on Django 1.7
Mention that we dropped Django 1.3.x support in changelog.
Fix deprecation warning