Adds basic support for event listings and pages

- Collapses all migrations for core app to start fresh.

- Removes a lot of cruft from core app that was held over from the wagtaildemo site.
Support index listing of standard pages

- Modify the reviews.yml files to create a StandardIndexPage which can only have StandardPage as children
- Put in a demo template for how to render child pages
- Fix the bug with menu_title on NavigationItems and some page types
Use settings file instead of args if available
Merge branch 'master' of git://github.com/bgrace/wagtail-commons