Add SECRET_KEY to settings file for docs to fix docs builds on Django 1.5
Branch: release-0.12.0
Refs #274: Write best practices for RapidSMS apps and Bootstrap

Branch: 274-bootstrap-practices
Branch: (no branch)
Merge remote-tracking branch 'rapidsms/release-0.12.0' into docs/messagelog

Conflicts:
	rapidsms/contrib/messagelog/templates/messagelog/index.html