Corrected animation curve enum usage.

1. Sometimes `UIViewAnimationCurve` enum values were used in a `UIViewAnimationOption` context. For instance, instead of `UIViewAnimationOptionCurveEaseIn` you used `UIViewAnimationCurveEaseIn`.

2. In one case (:1527), it looks like it was assumed that `EaseOut | EaseIn` would produce `EaseInOut`. It does not; it produces `Linear`. Look at the enum values in `UIView.h` and you'll see that this is true.

It would be pretty cool to expose this curve selection to the user, say to have two or four properties for which curve value to use for opening from fully closed, opening while another is ledged, etc.