Admin / Creator ability to delete events (#247)

Admin and creator ability to delete events. Delete option is hidden from non admin / creators.

https://github.com/18F/midas/issues/247
Turns out you don't even need the `projUtils.authorized` method -- you could call the `ProjectOwners` model directly with something like 

```nodejs
ProjectOwners.find()
.where({ projectId: ## })
.where({ userId: userId })
.exec(function ... {} );
```