Update the release notes for v1.7
Update the release notes for v1.7

nickburlett/feincms,joshuajonah/feincms,joshuajonah/feincms,matthiask/django-content-editor,nickburlett/feincms,mjl/feincms,matthiask/feincms2-content,feincms/feincms,joshuajonah/feincms,matthiask/feincms2-content,nickburlett/feincms,michaelkuty/feincms,matthiask/django-content-editor,joshuajonah/feincms,mjl/feincms,matthiask/feincms2-content,michaelkuty/feincms,michaelkuty/feincms,nickburlett/feincms,mjl/feincms,michaelkuty/feincms,feincms/feincms,feincms/feincms,matthiask/django-content-editor,matthiask/django-content-editor