Only green/purple/red are supported

Looks like there's a restriction on what map pins work:

``` objc
if ([phAnnotation.pinColor isEqualToString:@"120"])
    annView.pinColor = MKPinAnnotationColorGreen;
else if ([phAnnotation.pinColor isEqualToString:@"270"])
    annView.pinColor = MKPinAnnotationColorPurple;
else
    annView.pinColor = MKPinAnnotationColorRed;
```
