Big pile of suggested tweaks, mostly for site-independence

[lewiscollard]

• Content type URLconf is specified as urlconf = "lcfi.apps.events.urls" - should use {{ project_name }}.apps.events.urls
• hero_super_title is specified but many sites will not use supertitles. Maybe hero_title could be omitted as well?
• end_date can be made optional, just assume it's a single-day event if only one date is specified (make sure emptiness is checked in the date property)
• get_summary checks for a non-existent summary field (perhaps adding a summary field would be a good idea)
• Add an optional location field? I can't think of any recent projects that would not benefit from it.