Rename customActivityItems

[pimnijman]

I was looking for a way to set specify the URL that would be shared by the action button. I found the customActivityItems array instead.

customActivityItems suggests an array that will be used as the activity view controller's activity items, while this array will be used as the activity view controller's application activities.

if(self.customActivityItems != nil) {
    [activities addObjectsFromArray:self.customActivityItems];
}

UIActivityViewController *controller = [[UIActivityViewController alloc] initWithActivityItems:@[URLForActivityItem] applicationActivities:activities];

Suggestion: Rename customActivityItems to customApplicationActivities
or at least warn about this confusing in a comment.