This designated initializer is getting really long! Would it be better to default some of these values and have a simpler interface?

e.g.
```objc
VPLLocationPromotion *promotion = [[VPLLocationPromotion alloc] initWithCenter:appleHQLocation 
                                                                         range:3000
                                                                    identifier:@"My Promotion name"
                                                                        action:^{ }];
```
Then.. if we need to set things to be not-default
```objc
promotion.showOnlyOnce = NO;
promotion.startDate    = someDate;
promotion.endDate      = someOtherDate;
```